# Interactive sessions can't connect after idle

**URL:** <https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939>\
**Category:** Get Help\
**Created:** [August 7, 2026, 2:42pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939 "2026-08-07T14:42:45Z")\
**Posts on this page:** 19\
**Page:** 1

<div class="post-metadata">

**Author:** ![dsajdak](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/dsajdak/32/44_2.png) [@dsajdak](https://discourse.openondemand.org/u/dsajdak)\
**Post date:** [August 7, 2026, 2:42pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/1 "2026-08-07T14:42:45Z")

</div>

We’re running version 3.1.16 and having a similar problem to this [older topic](https://discourse.openondemand.org/t/interactive-sessions-timeout-and-are-unable-to-reconnect-infrequently/1442).

Our users launch an interactive session, step away, and then when they try to reconnect they see a VNC error rejecting the authentication:

 ![novnc-error](https://us1.discourse-cdn.com/flex015/uploads/osc/original/2X/0/0467fc44bcbf402973309e4f7ebf059f9ec8f7f1.png)

I can sometimes replicate this simply by disconnecting from the session and reloading the browser window. Then when I try to reconnect I see this error. The “view only” link works to connect to the session and see what is running.

I’ve been unable to find a fix for this and the users have to cancel their jobs and start over. Does anyone have any suggestions?

Thanks,  
Dori

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<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [August 19, 2026, 3:08pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/2 "2026-08-19T15:08:04Z")

</div>

Sorry for the delay in response Dori.

When you say “they try to reconnect” are you saying they try to connect on the same page/refresh that page or are they trying to reconnect through the button `Launch <cluster> Desktop>`? The former won’t work because these passwords are one time use. Every time you connect using a given password, it regenerates a new one for the next time. The latter should continue to work because the card should be able to pick up the newer password.

When I refresh the page once, I just get `authentication failed`. But if I continue to refresh the page - I get that message - authentication failed. client temporarily disabled.

However if I navigate back to OnDemand, the `Launch <cluster> Desktop` button still works using the new password.

So I think it may be a user error - refreshing that page won’t work, but using the `Launch <cluster> Desktop` button in OnDemand should continue to work.

If that button stops working, let me know and we’ll continue to look at it.

---

<div class="post-metadata">

**Author:** ![dsajdak](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/dsajdak/32/44_2.png) [@dsajdak](https://discourse.openondemand.org/u/dsajdak)\
**Post date:** [August 19, 2026, 6:20pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/3 "2026-08-19T18:20:01Z")

</div>

Hi Jeff,

No problem! We were looking into things on our end too. I am able to replicate this on demand (no pun intended!) now. I start up a session (desktop, app, doesn’t matter) and click the button to launch it. Once that new tab or window with the session is open, it works. If I close the tab and click the button to launch it again, I get the connection error. We thought it might be a firewall issue but confirmed in our dev environment that isn’t the case. There isn’t anything in the user nginx logs or the job logs indicating a problem. Are there other logs we could be looking at that might indicate what might be causing the problem?

Thanks,  
Dori

---

<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [August 19, 2026, 6:35pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/4 "2026-08-19T18:35:19Z")

</div>

Interesting.

You should see messages like this in your `output.log` as you generate new passwords. Every time you successfully connect it should regenerate a new password. Maybe you’re clicking the card too soon as it hasn’t picked up the new password yet? Or maybe there’s some NFS lag where the file is being updated on the compute node, but the web node is still reading the old file?

When I click the button on our 4.2 instance, it disables it for a bit so I can’t click it that fast.

```auto
(polkit-mate-authentication-agent-1:3387467): polkit-mate-1-WARNING **: 10:57:01.157: Unable to determine the session we are in: No session for pid 3387467
Setting VNC password...
Generating connection YAML file...
Setting VNC password...
Generating connection YAML file...
Setting VNC password...
Generating connection YAML file...
Setting VNC password...
Generating connection YAML file...

```

---

<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [August 19, 2026, 6:38pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/5 "2026-08-19T18:38:10Z")

</div>

Or maybe the page is failing to update the card. If you open your network tab on your ‘my interactive sessions’ page you should see something like this where the browser is querying the backend for new information (including a new password).

 ![image](https://us1.discourse-cdn.com/flex015/uploads/osc/original/2X/c/cb40dc328acd55c3d7e3590f2c9dfbd13a4c0ea1.png)

---

<div class="post-metadata">

**Author:** ![dsajdak](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/dsajdak/32/44_2.png) [@dsajdak](https://discourse.openondemand.org/u/dsajdak)\
**Post date:** [September 1, 2026, 1:01pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/6 "2026-09-01T13:01:19Z")

</div>

Hi Jeff,

Here’s an update on what we’ve seen and tested.

- Doesn’t appear to be browser based. It’s happening in Chrome, Firefox, and Edge
- I can’t replicate it immediately with interactive apps, including VNC based ones like the Matlab app. It’s only desktops. Eventually I can get the Matlab app to break by closing and reopening the browser tab with the session a few times.
- When it’s working, I’m seeing the output.log file indicate that a new VNC password is generated every time I click the button to launch the app. When it’s not working, I only see this with the initial launch of the desktop but not afterwards

```auto
Setting VNC password...
Generating connection YAML file...
Setting VNC password...
Generating connection YAML file...
Setting VNC password...
Generating connection YAML file...
Setting VNC password...
Generating connection YAML file...
Setting VNC password...
Generating connection YAML file...
Setting VNC password...
Generating connection YAML file...

```

- The non-VNC apps (Rstudio, Jupyter) work fine with no issues. Even if the session times out, the user can click the button and get a new one.
- The view-only links work fine for all the apps

We’re not seeing anything in the user logs, job logs, or the network info in the browser. We do have plans to update to 4.x in the next few months but aren’t prepared to do that right now. This is causing an issue for users that start something running in their session and leave it. Then they can’t connect back to it and have to resubmit their jobs which is a big issue for our GPU users who wait a long time to get a node. We’re just unsure what else we can check or what could be causing this.

Thanks for any help you can provide!

Dori

---

<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [September 1, 2026, 1:27pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/7 "2026-09-01T13:27:16Z")

</div>

> [@dsajdak](#):
>
> - When it’s not working, I only see this with the initial launch of the desktop but not afterwards

This seems to be the biggest clue. This is how this is supposed to work

- We set an initial password - this log line in `output.log`, `Setting VNC password...`
- We scan the `vnc.log` for a specific string to regenerate the password. You can see the log line `Scanning VNC log file for user authentications...`  
[ood\_core/lib/ood\_core/batch\_connect/templates/vnc.rb at 3290b0a6ae8654b043fe761314d79a4a4a699899 · OSC/ood\_core · GitHub](https://github.com/OSC/ood_core/blob/3290b0a6ae8654b043fe761314d79a4a4a699899/lib/ood_core/batch_connect/templates/vnc.rb#L186-L192)
- When we see that string we’re regenerating the password so it’s a one time use only password.

I wonder if you can share the full `output.log` and `vnc.log` of a desktop that stopped working?

I can’t quite imagine why it would stop working, but maybe that back-grounded `tail` process stopped for some reason?

I’m trying to replicate now, but you should be able to find a `tail` process like this in the users’ job in question.

```auto
[johrstrom ~()] 🐸 ps -elf | grep johrstr | grep tail
0 S johrstr+ 3663189 3663184 0 80 0 - 55252 hrtime 09:15 ? 00:00:00 tail -f --pid=3662923 vnc.log

```

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<div class="post-metadata">

**Author:** ![dsajdak](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/dsajdak/32/44_2.png) [@dsajdak](https://discourse.openondemand.org/u/dsajdak)\
**Post date:** [September 1, 2026, 2:57pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/8 "2026-09-01T14:57:58Z")

</div>

Hi Jeff,

Thanks for confirming. That’s how we understood it too. I’m attaching both those files. I’m not seeing that process at all for the user.

Dori

[output-log.txt](https://discourse.openondemand.org/uploads/short-url/o2W74ZF38Pb1BhztPD401PUvrsc.txt) (4.5 KB)

[vnc-log.txt](https://discourse.openondemand.org/uploads/short-url/3vOpeENmluZqaskwl0or9ywjobn.txt) (5.1 KB)

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<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [September 1, 2026, 3:32pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/9 "2026-09-01T15:32:08Z")

</div>

Is it specific users or are you able to consistently replicate it?

Here’s the PID I’m waiting for in my example (3662923) - you see it’s the `script.sh`. Odd that the tail on the PID would fail, but I’m guessing the actual PID/script.sh is still alive?

```auto
johrstrom ~()] 🐨 ps -elf | grep johrstr | grep 3662923
0 S johrstr+ 3662923 3662849 0 80 0 - 55852 do_wai 09:14 ? 00:00:00 bash /users/PZS0714/johrstrom/ondemand/data/sys/dashboard/batch_connect/sys/bc_desktop/cardinal/output/4bec98e0-63a7-46f5-ad0c-1db5e6842f66/script.sh
0 S johrstr+ 3662996 3662923 0 80 0 - 164497 do_pol 09:15 ? 00:00:00 mate-session
0 S johrstr+ 3663189 3663184 0 80 0 - 55252 hrtime 09:15 ? 00:00:00 tail -f --pid=3662923 vnc.log

```

---

<div class="post-metadata">

**Author:** ![dsajdak](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/dsajdak/32/44_2.png) [@dsajdak](https://discourse.openondemand.org/u/dsajdak)\
**Post date:** [September 1, 2026, 3:50pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/10 "2026-09-01T15:50:29Z")

</div>

Sorry, long username was getting cut off. I am seeing that process.

```auto
ps -elf |grep dsajdak|grep tail
0 S dsajdak+ 826775 826773 0 80 0 - 634 - 11:08 ? 00:00:00 tail -f --pid=826558 vnc.log

ps -elf |grep dsajdak|grep script
4 S dsajdak+ 825968 825959 0 80 0 - 1208 - 11:07 ? 00:00:00 /bin/bash /var/spool/slurmd/job25946772/slurm_script
0 S dsajdak+ 826558 825968 0 80 0 - 1196 - 11:08 ? 00:00:00 bash /user/dsajdaktest/ondemand/data/sys/dashboard/batch_connect/sys/bc_desktop/20-desktops/output/db22a04e-f3c0-4374-9b70-f56b54e18ae7/script.sh
1 S dsajdak+ 826773 825968 0 80 0 - 1241 - 11:08 ? 00:00:00 /bin/bash /var/spool/slurmd/job25946772/slurm_script

```

This is happening for all users, unfortunately.

---

<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [September 1, 2026, 4:24pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/11 "2026-09-01T16:24:19Z")

</div>

OK, we run turbovnc 3.1.1, I’m trying to build 3.1.2 to replicate. We may have to meet so I can see this interactively.

---

<div class="post-metadata">

**Author:** ![dsajdak](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/dsajdak/32/44_2.png) [@dsajdak](https://discourse.openondemand.org/u/dsajdak)\
**Post date:** [September 1, 2026, 6:12pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/12 "2026-09-01T18:12:11Z")

</div>

I tried to take a screen recording and I can’t replicate it consistently now. Very odd! I can even login to OOD from another browser and connect to a running session without issue. Right up until it stops working. They used to be immediately but now I have to connect a bunch of times before it finally fails. We’ll keep looking to see what might be causing it!

---

<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [September 1, 2026, 7:04pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/13 "2026-09-01T19:04:03Z")

</div>

Do you have availability to meet later this week? I think I’d like to see it in person if you can replicate consistently, which I guess you can’t anymore. I’ll still think on it from my side.

Just tested quickly with turbovnc 3.1.2 and it seemed OK.

---

<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [September 3, 2026, 6:09pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/14 "2026-09-03T18:09:15Z")

</div>

Thinking about this a little more - I wonder if a simple page refresh doesn’t fix it? That is when it starts happening, just refresh the ‘My Interactive Sessions’ page to pickup the new password would work.

---

<div class="post-metadata">

**Author:** ![dsajdak](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/dsajdak/32/44_2.png) [@dsajdak](https://discourse.openondemand.org/u/dsajdak)\
**Post date:** [September 8, 2026, 5:43pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/15 "2026-09-08T17:43:56Z")

</div>

Unfortunately, no, that doesn’t work. In fact, when I do that I can almost always get it to break.

---

<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [September 8, 2026, 7:24pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/16 "2026-09-08T19:24:45Z")

</div>

Odd. What about the network tab in the browser when it fails. Do you see the same 200 OK’s that I’ve given above or do those requests fail?

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<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [September 14, 2026, 7:11pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/17 "2026-09-14T19:11:27Z")

</div>

I have tried to replicate in a 3.1 instance in development mode, but haven’t got much luck.

I’d say if you can replicate pretty consistently then we should set up a time to meet and debug it interactively since you’ve got a support subscription.

---

<div class="post-metadata">

**Author:** ![dsajdak](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/dsajdak/32/44_2.png) [@dsajdak](https://discourse.openondemand.org/u/dsajdak)\
**Post date:** [September 21, 2026, 7:37pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/18 "2026-09-21T19:37:32Z")

</div>

Hi Jeff,

OK Andrew has emerged from the rabbit hole and solved our problem. He upgraded to version 4.2 and the problem still existed so we knew it was something on our end. I won’t get into the gritty details but wanted to update this for future people who may come across similar issues. We are running different versions of NFS on our compute nodes and the ood/login nodes. This wasn’t a problem until we put another storage system online that has some slightly different settings and the data wasn’t replicating correctly. So OnDemand was creating a new connection.yml file that was accessible on the compute node but the VNC session wasn’t picking up the new file; it could only access the old one, causing the session to disconnect.

Thanks for the assistance you provided!

Dori

---

<div class="post-metadata">

**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [September 21, 2026, 8:06pm UTC](https://discourse.openondemand.org/t/interactive-sessions-cant-connect-after-idle/4939/19 "2026-09-21T20:06:22Z")

</div>

Thanks for letting me know! I suspected NFS lag, sorry if I didn’t mention it early enough or often enough. Even more sorry that that’s what it ended up being!

Glad to hear (or assume) the upgrade went smoothly!