"noVNC - failed to connect to server" on Chrome or Edge Chromium, works on Firefox

[Elrendhel]

Greetings!

My first Proxmox VE and it's working incredibly well! All of my VMs work fine, no problems other than the problem defined below.

However, I do have a minor problem when attempting to use the WebGUI Interface and the Console section under each VM. The error is stated as "noVNC - failed to connect to server". This appears at the top of the console section that remains black, and it only impact me while I'm using Chrome or Edge Chromium. It seems to work fine when using Firefox.

My install is fresh on Proxmox CE 7.1-10, and Chrome is my browser of choice.

I have tried the following:

• disabled Chrome security for a few minutes (Settings > Security & Privacy > Security > No Protection) and that did not help whatsoever.
• I have tried using a different Display such as VMWare, Standard VGA, and VirtIO-GPU, and rebooted each VM after each change to no avail.
• I have tried to switch to a different TTY with Ctrl + Alt + F1 or Ctrl + Alt + F2, but this did nothing as well.

This happens for both my Linux VMs (Ubuntu) and my single Windows VM.

 

[oguz]

hi,

This appears at the top of the console section that remains black, and it only impact me while I'm using Chrome or Edge Chromium. It seems to work fine when using Firefox.

seems to be a browser issue in that case (if it works with one but not the others, then likely it's not an issue on the PVE end).

maybe you have some add-ons on your chrome/edge that are messing with it? have you tried clearing browser cache and/or using incognito mode without extensions?

it's also possible that some antivirus software don't like your browser making external connections (various internet security etc. software can block this)

 

[Elrendhel]

Greetings oguz!

Thank you for taking the time to assist me! I would entirely agree that it is something to do with the way that Chrome (and by extension Edge Chromium) operates. Specifically, I think it's the way that they treat security via the HTTPS protocol.

Yes, I did in fact try several other strategies but neglected to site them, my bad:

• I have deleted all browser-cache and windows temp file-cache, same problem...
• I have disabled all "extensions", same problem...
• I have tried incognito mode with no extensions, same problem...
• I did try to import the self-signed certificate into Chrome, but it didn't get rid of the HTTPS error. Of course same problem...
• I created a whole new windows profile with no other programs set to autoload, and all AV disabled and all of the above. Of course same problem...

I still think that if I fix the HTTPS issue, Chrome (and Chromium based Edge) will start working properly to allow noVNC to operate.

Is there a better way to get the HTTPS certificate issue fixed?

Also, I would point out a discrepancy in the way that Proxmox is reporting the problem. While the top of the noVNC screen shouts "Can't connect to server" (screenshot attached), when I look at the error message in the Task Log, it says "Connection Timed Out" (screenshot attached as well), if that helps.

Thank you again for your assistance in this endeavor, it is greatly appreciated!

-Elrendhel

 

[oguz]

I would entirely agree that it is something to do with the way that Chrome (and by extension Edge Chromium) operates

could you tell us which versions of the browsers you're using?

also are you on windows 10 or 11? or which version?

and rebooted each VM after each change to no avail.

the VM settings should be fine (since it works in firefox). please revert them if you haven't (to avoid false positives while testing for this issue)

Is there a better way to get the HTTPS certificate issue fixed?

how do you mean?
did you add a custom certificate? how exactly did you do so?
which HTTPS error are you talking about? could you send a screenshot please?

 

[Elrendhel]

could you tell us which versions of the browsers you're using?

Chrome Version 97.0.4692.99 (Official Build) (64-bit)
Edge Browser Version 97.0.1072.76 (Official build) (64-bit)
Firefox Version 96.0.3 (64-bit)

also are you on windows 10 or 11? or which version?

Windows 10 Professional v21H2 (OS Build 19044, 1466) on all 3 PCs (2 Desktop, 1 Laptop)

the VM settings should be fine (since it works in firefox). please revert them if you haven't (to avoid false positives while testing for this issue)

Already done.

how do you mean?
did you add a custom certificate? how exactly did you do so?
which HTTPS error are you talking about? could you send a screenshot please?

On one of three different PCs having this problem, I added the CA Cert listed in Datacenter > Node > Certificates > pve-root-ca.pem. Again, no change.

This process involved the following steps:

1.) opening the CA file, copying the contents from ----Begin all the way to the End---
2.) paste them into a text file and save the text file.
3.) rename the file to *.crt.
4.) open the file and then import that into certificate store with certificate wizard:
a.) Install Certificate button - 2022-01-31.png
b.) Store Location local machine - 2022-01-31(1).png
c.) Certificate Store - 2022-01-31(2).png
d.) Completing Wizard - 2022-01-31(3).png
e.) Import Successful - 2022-01-31(4).png

This did *NOT* fix the issue with HTTPS being broken

 

[Ruklaw]

Do you have a proxy server setup? I seem to recall that Firefox uses it's own proxy server settings, where Edge and Chrome will use the system proxy settings (from the 'Internet Options' widget).

Most likely explanation to my mind would be that novnc uses a non standard port which the proxy server is blocking, but firefox isn't using the proxy server.

 

[Elrendhel]

Greetings Ruklaw!

Thank you for posting your thoughts on this issue, the more help, the merrier!

Since I'm having the same problem on 3 different computers, I'm mostly just surprised that more folks are not having this same problem, although I'm more of a hobbyist/homelab, so I may be the rare lark. Especially if most IT folks are connected with a legit FQDN and full Certs to keep it HTTPS.

Do you have a proxy server setup? I seem to recall that Firefox uses it's own proxy server settings, where Edge and Chrome will use the system proxy settings (from the 'Internet Options' widget).

No, I am not setup with a Proxy Server.

Most likely explanation to my mind would be that novnc uses a non standard port which the proxy server is blocking, but firefox isn't using the proxy server.

Is there any way that you can think of that I can test this theory? I'm game to try an experiment if you can think of one to try...

 

[Ruklaw]

Well, if you aren't using a proxy server then I'm presumably wrong, although a good tool for investigating is Telerik's Fiddler - it runs as a local proxy server so that you can see all communication going on between your web browser and the web server, in this case Proxmox.

You might want to try looking at the developer tools in Chrome/Edge first as they should show you which network connections are being attempted and presumably failing - it could still be some kind of anti virus product that is silently blocking the traffic for some reason.

 

[nikin]

Hi
I also do experience same issue. FF works fine, but opening console with other browsers does fail.
I do use selfsigned SSL so wonder if that might be the problem. Maybe Chrome and Edge does deployed more strict policy for WSS connection i.e. valid SSL is required. Until recently it used to work fine with all browsers.
Task viewer shows :

TASK ERROR: command '/usr/bin/termproxy 5901 --path /nodes/node-02 --perm Sys.Console -- /usr/bin/ssh -e none -t 198.96.0.147 -- /bin/login -f root' failed: exit code 1

Browser dev tools does show: "app.js?ver=1.2.0-3:10807 WebSocket connection to 'wss://xx.x.x.x:8006/api2/json/nodes/node-01/qemu/150/vncwebsocket?port=5900&vncticket=PVEVNC%3A621F9B1F%3A%3AMJI%2FiEG8ar22xCP%2BAgOePfmX9K34YgJmyZz6frIB%2F26GEWiTcb%2F6TxI8ezULTOHs8uf%2B7XMkBz%2Fvt8%2' failed:"

 

[ZipTX]

Same Issue here. I typically use Edge [103.0.1264.44] and Brave [103.0.5060.114]. I installed Firefox [102.0.1], hoping this would be a good workaround. No luck with Firefox. Our clustered hosts are a mix of 7.1-7 and 7.2-3. Both versions have the same behavior. All the hosts have a valid ACME certificate from LetsEncrypt for the host. Each host works fine with its hosted VM's but no other hosts in the cluster. No proxy server is used.

 

[ZipTX]

A bit more research. I was getting a "Host key verification failed. TASK ERROR: Failed to run vncproxy."

To Fix:
A) On the host I was using the GUI, I connected to the CLI and cleared out the /root/.ssh/known_hosts
B) I executed

ssh-copy-id -o 'HostKeyAlias=host02' root@192.168.0.12

for every host name in the cluster. This provided a way to re-add the Host Key and verify the root key was correct on the other host.

Used this as reference: https://forum.proxmox.com/threads/c...to-server-host-key-verification-failed.78957/

This resolved my issue. All consoles on every other host in the cluster are now working through the host I'm connected to.

 

[maxudak]

I had a similar problem and I saw that it depends on the vm settings when creating it. Try to recreate the vm and leave everything as default. In my case it helped.

 

[ardatun]

I've got a similar error "failed to connect to server" and I was not able to boot a VM.

1) I added an additional network bridge (vmbr1) in the pve node (but didn't click on the apply configuration button)
2) Added an additional network device to the host using this new vmbr1
3) Starting the host was not possible and I was getting this error: "failed to connect to server"

After clicking the "Apply Configuration" button in the network settings of the pve node, the error dissapeared and the vm booted normally.

Some improvements like the following can help users like me and avoid confusion:

- Hiding the new vmbr1 bridge which is not activated yet(which is in the pending state) when the user wants to use it with a network card on a VM.
- Displaying a warning which says "The bridge vmbr(n) for the network interface is not activated yet" when the user clicks starts the VM.

Kind regards