Handling the Dreaded Synology DSM “Cannot Connect To The Internet” Error

I finally had a couple of seconds to rub together to try out the mixed-environment Synology backup workflow that I’ve been meaning to get around to, but needed to do some quick updates to some boxes that I have not used in a while. Little did I know that I’d have to postpone it, yet again.

[Update 2017.06.13. For this exercise I’m assuming you have your Synology connected to a router/switch, not directly attached to a computer. If you attach the Synology directly to a computer that is not running DHCP you will get a 169.254.X.Y address, it will not connect to the Internet and these instructions won’t work, I’m afraid.]

When you log into the DSM Control Panel, you’ll see a familiar flag connected to the icon, letting you know that there is an update to be made:

You've got updates!

You’ve got updates!

When you click on the update, the control panel will open up and you can see the little flag bounce at you:

Pick me!

Pick me!

When you click on the Update and Restore icon, what you should see is this:


Update at will, ensign.

Instead, sometimes you can get this:

Ah, crap. Now what?!

Ah, crap. Now what?!

(Eagle-eyed readers will notice that these last two screenshots are from two different machines. Fear not: it happened with both of them).

Ah, yes. The evil, “Connection failed. Please check your Internet Connection” error. This problem has confounded many a poor soul. Rumor has it that the only people to have successfully beaten this devilish problem are the Ancient Mayans, who also were able to count to 2012 and start over without panicking about the end of the world.

Now before you run screaming to the streets or try to wipe your Synology clean, here are a couple of things you can try.

First, navigate to the control panel if it’s not already showing (that’s the icon I showed up above). Then you want to find the icon labeled “Network.” It looks like a little house sitting on top of a sewer line (and if you know anything about networking, you’ll realize just how appropriate that is):


The screen that pops up will tell you what your network settings are. Most of these should be filled in for you. There is, however, two lines that you need to look at: The Default Gateway and the IPv6 Default Gateway.

Look at the pretty circles.

Look at the pretty circles.

You’ll notice a couple of things. First, there is no Default Gateway listed. This is bad. We’ll get to what these things mean in just a moment. For now, let’s fix this.

Default Gateways

Click on the “Edit” button next to the Default Gateway. It should look something like this:

I see you now!

I see you now!

Once the LAN configuration is populated (i.e., it shows up), you can click on OK. The Network control panel should now have this value next to it:

Where you been all my life?

Where you been all my life?

But what happens if it’s not there? Everybody panic!!

Wait, wait. No, that’s not right. Let’s try this instead. Click on the next tab over, the “Network Interface” tab. You’ll see at least one connection listed.

Getting closer...

Getting closer…

Go ahead and click on “Edit” with the interface highlighted, as it is in the picture above. Here is where your mileage may vary. If you have your Synology Diskstation set up to get its network configuration from your router, it will have “Get network configuration automatically (DHCP) chosen for you. Personally, I like to have my devices on static IP addresses, so I use the manual configuration option:

Why do it the easy way? Manual config all the way!

Why do it the easy way? Manual config all the way!

If you didn’t see the default gateway in the previous step, you may want to check to make sure that the checkbox is selected to “set as default gateway.”

One word of caution: Do not put in arbitrary numbers here. These numbers mean something, so if this is all Greek to you then simply keep the “Get network configuration automatically (DHCP)” checked and don’t worry about this stuff.

While we’re on this screen, however, we need to make some changes to the IPv6 settings as well. Fortunately, it’s just one tab over. There’s only one change you have to make here, and it’s an easy one:

IPv6 is a big bowl of "nope"... for now.

IPv6 is a big bowl of “nope”… for now.

Yup. Just turn IPv6 off.

So what does this stuff mean? The Synology needs to know where to find its way out of the network to see the world (fly! Be free, little Synology!). The Default Gateway is just that – it’s the gateway to the world (online, at least), and the “default” part of it means that this is where the Synology should look if it wants to communicate with the outside world. Since we want to know if Synology has an update that we need, and Synology is in the outside world, this Synology does not know where to go.

The second thing you’ll see is that the IPv6 default gateway does have an address listed. Yes, it’s the fe80::5a6d:8fff:fef6:a226 gibberish that’s next to the words “IPv6 default gateway.” Nifty how that works, eh?

When you turn it off, this default gateway should disappear, and it should look something like this:

Which way did he go, George?

Which way did he go, George?

DNS Servers

So, we figured out how to tell the Synology to find devices outside of our home network. This is the “if you don’t know where to go, go here” setting. But once the Synology goes there, then what?

The DNS Server is the place to do that. It’s a server that keeps track of what all these strange numbers mean. They’re the devices that you can ask to find out how to turn google.com into an address that the computers understand, and vice versa.

Speaking of Google, Synology recommends using their DNS server address as the “Preferred DNS Server,” so you should make your system look like this:

The Goobles to the rescue!

The Goobles to the rescue!

Now, in this case, you want to make sure that the numbers match exactly. The periods (full stops) and all. No spaces. You do not have to have an alternative DNS Server, but I put my default gateway as my alternative if, for whatever reason, Google’s DNS server doesn’t respond.

Here Goes Nothing

When I updated my two boxes, I had very different reactions from them. They both gave me the “Could not connect” error. What was even stranger was that on one of the boxes, I did not have to remove the IPv6 setting for it to work – a simple restart after fixing the default gateway and DNS server gave me complete connectivity. The other one, though, was a true PITA.

I tried using Synology’s QuickConnect, and it didn’t work either. Then, I had a bit of a minor success. I was able to turn on the NTP server (that’s the service that lets the Synology know what time it is, according to the US Government’s NIST time servers). Then, miraculously, QuickConnect worked. However, the DSM update continued to give me that error.

Then, about 5 minutes later, the DSM update was giving me what I needed to see:



My best guess is that the time it took for the routing tables to be updated took far longer than either the DSM user interface or my patience expected. I had restarted the box a couple of times in the interim, hoping that it would take, but I think I might have disrupted the population of the tables, and the DiskStation simply restarted the process again. I think that patience is far more useful a tool in this instance than I first thought.

Other Options

Update 2018.06.25. Several readers have written in to say that this has helped them figure out what’s going wrong, and others have offered suggestions for what have helped them fix the issue as well. I have not attempted these, but I’m leaving them here as a courtesy for the reader to attempt, should the above steps fail to resolve the issue.

  1. Change the admin account password. Every Synology has an “admin” account. Some people have had luck changing the password. It’s not clear why this is an issue; the best I can think of is that newer versions of DSM are requiring a stronger password for allowing incoming/outgoing traffic, but that’s just a guess. In any case, try changing the Synology “admin” account password.
  2. Modify DNS settings. I do not use the Synology’s DNS settings, so this was not an issue for me. However, another reader is using Synology’s RT1900ac router, and offered the following advice:For the DHCP server, “forward known DNS server” was disabled. Also, IPV6 was setup as AUTO in STATELESS mode. With these settings DSM update could not connect to the internet.Since the issue seems to be DNS related, I changed these two settings: a) I enabled “forward known DNS server”, and b) I changed my IPV6 setup to be stateless DHCPv6. I’m not sure which fixed the problem, but my DSM was immediately able find and install updates.
  3. Check your time zone/time server (NTP Server). If the date/time setting is out of whack, it can create issues.
  4. If the Diskstation switches to offline mode after a few seconds, try whitelisting the Synology server in uMatrix. DSM may detect that the browser won’t able to open the pages and switch to offline mode. The Synology update server may be found after that. Try pinging arbitrary addresses to double-check. (Thanks and h/t to Carsten Groß)

As I said, I have not attempted these fixes myself (hence no screenshots), but readers were kind enough to offer additional suggestions and if it helps you in your hour of need, please let me know. YMMV.

Synology’s Take

I contacted Synology’s tech support to find out why this might be happening, since there were no reports in the logs about what had happened during the update process. Here’s what I got, verbatim:

Upon further investigation I see there were some bugs in the past with a disappearing gateway, primarily if the connections were bonded during the upgrade. It was a bug that should be resolved now and should not typically happen.

Now, it is true that one of the Synology DiskStations I was updating had bonded network interfaces, but that was also the one that fixed itself faster. True, I was updating to DSM 6.0 so perhaps the fix was already being applied at that point too. The device that I have been using as an example, however, only had one network interface so there was no link aggregation (or “bonding”) going on.

Even so, after I run the backup tests in a mixed DSM 5.2/6.0 environment, I’ll be needing to update this box to 6.0, so I’m fully expecting to need to refer back to this blog again if/when I lose network connectivity!


I did read some additional messages in the user forums that permissions problems could be to blame for this issue, but it was not so in my case. My gut tells me that is a different issue – the problem here is connecting to the Synology servers in order to determine whether there is an update, and if so which one. Permissions issues would likely only result once it has been determined that an update exists and then issues would arise when trying to save it to a local directory on the Synology. That’s my gut take on it, however, and certainly not something I’d defend to the death.

In any case, I hope that this is somewhat helpful to people (including myself). If this works – or if it doesn’t work – please feel free to leave a comment and let me know. Anything I missed? Please feel free to offer another solution to help out. 🙂


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  • Shane King November 12, 2017 at 00:16

    my problem was the timezone… it was on manual time and had the incorrect date / time. I set the date/time correctly (just used google NTP) and its now working.

    • J Michel Metz November 13, 2017 at 07:29

      Thanks for letting me know. It’s looking like this may be happening more often recently.

    • Jon December 5, 2017 at 12:58

      I will second the timezone being the issue. DSM stopped updating or connecting to the Internet all of a sudden. I had already gone through manually inputting the DNS, Gateway, etc info, rebooted multiple times, blew away network configs and recreated, etc and nothing worked. Stumbled upon this thread and was scanning through, when I saw the NTP comment. I knew it was already enabled, but went and hit “Synchronize with NTP server” on the Time tab. Viola! Everything started working with regard to Internet connectivity immediately. I wish I would have noticed what the previous time was set for before syncing. Thanks!

      • J Michel Metz December 5, 2017 at 12:59

        Thanks for confirming, and I’m glad this was helpful. 🙂

    • Mark M December 21, 2017 at 08:34

      You are a god among men – tried all of the above, saw this and decided what the hell can’t hurt – instant connectivity.

      • J Michel Metz December 21, 2017 at 09:49

        W00t! Glad it was helpful! I’m really glad that people are able to contribute to the knowledge base. 🙂

  • Chris November 13, 2017 at 20:40

    Thanks for this brilliant guide. I followed it step by step and it worked a treat. I updated to the google servers and left my gateway as the alternative.

    • J Michel Metz November 13, 2017 at 22:17

      That’s great. I’m glad it could be helpful. 🙂

  • Idus November 17, 2017 at 15:32

    Very nice step-by-step guide.

    Unfortunately – it just works half-way. My system update says it has the latest update. But NON of the (not already installed) packages in the Package center are shown. All I get after the above tutorial (and wait) is:

    “Connection failed. Please check your network settings”.

    …but every other service seems to work just fine. :-/

    Maybe letting it sleep over the night. 😉

    • J Michel Metz November 17, 2017 at 15:40

      A couple of things (troubleshooting blind here, please forgive anything you may have already tried):
      Since trying the steps above…
      Have you restarted the Synology?
      Have you checked the cables?
      Is it possible you may have skipped any steps?

      Please let me know your progress.


  • Barrage December 31, 2017 at 12:02

    Fantastic! This guide helped me restore connectivity in minutes! Many Thanks!

  • johnny5 January 4, 2018 at 15:35

    Great page. The problem was fixed either by using an updated DNS server or turning off IPV6. The default gateway info. was not erased on mine.

  • Tim P. January 7, 2018 at 19:54

    Worked like a charm, very first try – thanks for saving my sanity!!

    • J Michel Metz January 7, 2018 at 22:33

      Excellent. 🙂 Thank you for letting me know.

  • Rob January 13, 2018 at 23:53

    I just made mistake of bringing my 214+ up to date. Now I’m stuck with these Operation Failed and Connection Failure issues. I can’t access my shares, can’t save some settings, and just keep getting the Connection Error. I can’t update DSM since i’m on the latest.

    – It’s not taking my time settings but it’s already on NTP sync. I hit apply, then try to exit and it says I have unsaved changes.
    – I’m getting errors when going to the Users
    – My IPv6 is off

    This is killing me. I’m totally frustrated with this just from a simple upgrade.

    • J Michel Metz January 14, 2018 at 09:13

      What kind of errors are you seeing?

      • Rob January 14, 2018 at 18:07

        – When first in, it takes like 30 seconds to get to the Control Panel
        – Clicking on Update & Restore to check software update, I get ‘Connection failed. Please check your Internet Connection’. Clicking off and back on, it works. Looks to be intermittent.
        – When accessing my shares, I get Operation Failed. This happens when about 90% of the time when viewing or trying a read/write action.
        – It was not taking my time change settings. I was changing it to google to see if the timing change fixes things. After many many attempt, the changes finally took. Previously, I hit apply and it looked like it applied, but clicking out, it says I had unsaved changes.
        – Tried to install Log Center for advanced logging and got the ‘Connection failed. Please check your Internet Connection’.

        Would anyone recommend removing the bond interface and resetting it? Or trying a beta 6.2 software?

      • Rob January 14, 2018 at 18:28

        Also to mention, it takes like 5 minutes for me to be able to log into the DSM. Or at least it seems like 5 minutes from boot.

      • Rob January 14, 2018 at 18:32

        …And…It takes 2 minutes for Package center to come up on the screen. After that initial time, its ‘normal’ after that.

      • Rob January 14, 2018 at 18:35

        Sorry, one more. When I click User in Control Panel, it says ‘The operation failed. Please log into the DSM again and retry’. I really think I have a corrupt DSM install, but there is no way to do a reinstall.

      • Rob January 15, 2018 at 12:29

        I gave up troubleshooting. Looks like something went corrupt as I kept getting connection resets. The logs I was able to get showed a bunch of errors with the bond interface that I had. I think I read something about the DSM updates having a bug with a bond interface.

        Anyway, I did a reset and re-installed the OS. Upgraded to the latest and looks to be working well now. I currently have the links separated for now and won’t make a bond just to ensure the OS is going without issues. Thanks.

        • J Michel Metz January 16, 2018 at 08:27

          I’m really sorry I didn’t get the chance to respond earlier. I’ve been feeling a bit under the water.

          I think that’s pretty interesting about the bond reset. I think you’ve given me an idea to try for a problem I having with a new Synology re-install.

        • steve June 2, 2018 at 09:05

          I need help too, my DS411j is doing the same thing, reset it yesterday, initially found the nas in DSAssistant, tried the dchp and manual ip set up, both said error in configuring diskstation.
          Tried DCHP, manual, changing the DNS to and then again with the Router DNS neither made any difference. Still got config error.

          Tried to connect and reset again today but connection failed, cant find in finder or
          Ds Assistant. Tried another reset, but now literally nothing happens, no beep, nothing.
          Trying to turn off on the blue button doesn’t work either. Any ideas for starters..wait…or Yank the power cord? I have 4 2tb disks so no option to back up first sadly. Did have to do same last year and it survived so…

          also what is a bond? keep seeing people talk about it but no clue what is means.. could that be relevant for me too? Thanks

          • J Michel Metz June 3, 2018 at 10:01

            Did you get any more information about the error while trying to configure the Diskstation IP setup, or did it just say “error”? That’s always useful. 🙁

            It sounds like there might be more going on here than a setting not being taken. From time to time, my DS216 just decides to go off the reservation, and I’m forced to unplug and re-plug it back in. I do this when SA can’t see it and the blue light blinks quickly. Wait 30 seconds, and then plug it back in. Keep in mind, that it can take up to 5 minutes (no joke) for it to run its internal diagnostics and be seen on the network.

            If that doesn’t work, Synology’s 30-30-30 steps should also work (this is the link for their routers, but this works on Diskstation devices as well – I’ve done it for my DS416play. It won’t touch your data on the disk, it just resets the chassis configuration.

            Please let me know how it goes.

  • Sal February 11, 2018 at 12:05

    I followed all the suggestions and the DNS error, as well as failed network services test fails, and could not browse new packages persisted. I rebooted after every change. I changed from static to dynamic and back to static to clear my errors without rebooting.


    • J Michel Metz February 12, 2018 at 07:48

      Hi Sal, I’m terribly sorry that it wasn’t useful for you. Did this happen after an upgrade, or did it just start happening?

  • Ritchie Hicks February 12, 2018 at 04:57

    Incorrect DNS was the fix I needed. Thanks.

    • J Michel Metz February 12, 2018 at 07:47

      I’m glad it was useful. 🙂

  • John T February 24, 2018 at 03:04

    Brilliant article. Really helped me out. Donation made. Really loved your sense of humour through-out. Nicely done that man!!!

    • J Michel Metz February 24, 2018 at 11:37

      Thank you, and thank you so much for the donation. Much appreciated! 🙂

  • shmirker April 3, 2018 at 10:08

    Hi! Thanks so much for the article. The problem i have is there is no visible ‘EDIT’ button next to the default gateway. It’s driving me nuts!

    • J Michel Metz April 3, 2018 at 11:38

      Glad it could be helpful. Hidden buttons are quite frustrating.

  • Sreelatha April 10, 2018 at 07:15

    Hi, I accidentally changed the DNS settings on Ds1512 and did a reboot from the GUI. Then I lost connection and not able to connect to the Ds1512. The default web interface is coming up now. When I open this ip in URl, GUI is coming up with just DSM help button. There are no folders, control panel or anything else.

    How can I connect back to my network 192.168.0.xx without losing any configuration

    • J Michel Metz April 10, 2018 at 08:59

      Ugh. I hate when something like that happens. When you say “the default web interface is coming up now,” is this what is showing up in Synology Assistant? Or in an arp?

      In general my first stop for IP issues is Synology Assistant because each DiskStation uses zeroconf/Bonjour for self-assigned local addressing in addition to the default Class C address. Have you tried that?

  • Porter July 10, 2018 at 00:00

    You are the first blogger I have ever contributed money to. I hope great sponsorships come your way because I was really grateful for all of the helpful and valuable information you shared. If I were in a better financial situation, I would give more. I read A LOT of tech articles trying to learn about tech, and yours is really great. Thanks!

    • J Michel Metz July 10, 2018 at 06:06

      Thank you so much. I really appreciate the kind words and the donation. 🙂 There are a lot more articles to come, but finding the time to do them has been tough. My list is so long!!

      Once more, thank you. I really appreciate it. I’ll do my best to continue providing more content soon.

  • HS July 23, 2018 at 19:18

    Great Help! One last suggestion – the only one that worked for me – if you set a VPN – disconnect it first!

    • J Michel Metz July 24, 2018 at 05:57

      Yes, that is excellent advice! 🙂

  • Otakar Německý December 3, 2018 at 07:52

    Thanks a lot for help.

    • J Michel Metz December 3, 2018 at 08:11

      Glad it was useful. 🙂

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