# Unable to connect to server with ParaView 5.12
**URL:** https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110
**Category:** ParaView Support
**Created:** [January 3, 2024, 3:25pm UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110 "2024-01-03T15:25:40Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@NotDrJeff](https://discourse.paraview.org/u/NotDrJeff)
#### Post date: [January 3, 2024, 3:25pm UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/1 "2024-01-03T15:25:40Z")
I’m having the same issue with 5.11.2. Server log reports “client connected” but client is frozen with “waiting for connection to server”. Can’t use the “cancel” button either. The process has to be killed.
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### Author:  [@fpradelli94](https://discourse.paraview.org/u/fpradelli94)
#### Post date: [March 7, 2024, 6:50pm UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/2 "2024-03-07T18:50:28Z")
Same with Paraview 5.12.0. Client running on Windows 11 and Server on Ubuntu 20.04. Exact same version on both. Did anyone find a workround?
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### Author:  [@NotDrJeff](https://discourse.paraview.org/u/NotDrJeff)
#### Post date: [March 7, 2024, 10:20pm UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/3 "2024-03-07T22:20:50Z")
@fpradelli94 I didn’t find a robust solution to this, but I did find the issue to be temperamental. Sometimes it worked and sometimes it didn’t.
A few steps I tried that can sometimes help are: delete known\_hosts file in .ssh folder; run paraview as admin; install paraview as opposed to using portable version; reinstalling paraview; restarting client; or trying some combination of these.
I am not clear which, if any of these steps actually helped, but they seemed to fix the problem temporarily sometimes. Other times, these steps didn’t seem to help at all.
Sorry that that isn’t very helpful.
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### Author:  [@GregVernon](https://discourse.paraview.org/u/GregVernon)
#### Post date: [March 8, 2024, 4:36am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/4 "2024-03-08T04:36:45Z")
@fpradelli94 – I’ve found that if you use the regular (not headless) ParaView’s `pvserver` on the Linux server that it seems to work more robustly / connects quicker. For example:
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [March 8, 2024, 9:40am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/5 "2024-03-08T09:40:30Z")
@NotDrJeff : Are you using a special SSH setup ?
@fpradelli94 : just tested here, it works fine
@GregVernon : just tested here, it works fine
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### Author:  [@NotDrJeff](https://discourse.paraview.org/u/NotDrJeff)
#### Post date: [March 8, 2024, 10:52am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/6 "2024-03-08T10:52:30Z")
@mwestphal I’m not an expert on ssh, so I can’t say if it’s a “special” set up. I am in a university using an HPC that is on the same WAN. It could be a firewall or hostkey issue, but I really don’t know. I have encountered the same problem conneting from inside and outside our network. Ialso know I have issues with “domain name spoofing” warnings a lot, and I usually have to delete my known\_hosts file to get access to my HPC.
As mentioned, this is an intermittant issue for me. Very frustrating when it happens, but it doesn’t always happen, and usually trying some of the steps above will fix it, at least temporarily.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [March 8, 2024, 10:53am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/7 "2024-03-08T10:53:30Z")
Unless you are configuring ParaView to use SSH explicitely, ParaView client server mechanism does not rely on SSH at all.
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### Author:  [@NotDrJeff](https://discourse.paraview.org/u/NotDrJeff)
#### Post date: [March 8, 2024, 10:55am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/8 "2024-03-08T10:55:37Z")
@mwestphal sorry, I should have mentioned that I use an ssh tunnel to connect a localhost port to a port on the HPC.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [March 8, 2024, 10:59am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/9 "2024-03-08T10:59:41Z")
Then your solution is probably specific to your setup. Here is how I debug SSH tunelling in general:
>
>
> \*\*Server OperatingSystem\*\*
> any linux based os
>
> \*\*Client OperatingSystem\*\*
> Wi…ndows 10 with Spring Update
>
> \*\*What is failing\*\*
> There is definitely a bug in Microsoft OpenSSH implementation from 2018 Spring Update.
>
> How to test it :
> On the local (Windows 10), install Python3, Putty and make sure ssh is available.
> Then
>
> 1. Run a python http server in a terminal (on port 8000 by default)
>
> \`python -m http.server\`
>
> 2. Create a reverse connection ssh tunnel
>
> \`ssh -R 8080:localhost:8000 user@remote\`
>
> On the remote, connect trough the tunnel with telnet
> On The remote, connect to it trough telnet
>
> \>telnet localhost 8080
> Trying 127.0.0.1...
> Connected to localhost.
> Escape character is '^\]'.
> Connection closed by foreign host.
>
> The tunnel is still runnning but telnet disconnect almost instantly after the connection.
>
> If you replase \`ssh\` by the plink.exe from putty, it works flawlessly and you can connect with a browser.
>
>
> \*\*Expected output\*\*
> \`\`\`
> \>telnet localhost 8080
> Trying 127.0.0.1...
> Connected to localhost.
> Escape character is '^\]'.
> \`\`\`
>
> \*\*Actual output\*\*
> \`\`\`
> \>telnet localhost 8080
> Trying 127.0.0.1...
> Connected to localhost.
> Escape character is '^\]'.
> Connection closed by foreign host.
>
> \`\`\`
(this is about reverse tunelling but the usage of python server is a perfectly valid way to check the tunnelling is working)
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### Author:  [@NotDrJeff](https://discourse.paraview.org/u/NotDrJeff)
#### Post date: [March 8, 2024, 11:05am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/10 "2024-03-08T11:05:33Z")
@mwestphal Thanks Mathieu. I’ll have a look at that when I get a chance.
All the best.
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### Author:  [@fpradelli94](https://discourse.paraview.org/u/fpradelli94)
#### Post date: [March 13, 2024, 11:16am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/11 "2024-03-13T11:16:22Z")
Thank you guys for your kind support.
@NotDrJeff I am testing your recommendation. So far it didn’t work yet.
@GregVernon I am using the regular Paraview indeed.
@mwestphal I don’t know what’s happeining then. Might it be a problem related to my VPN? I am using a VPN to connect with the office network. In the office used to work fine.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [March 13, 2024, 11:17am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/12 "2024-03-13T11:17:04Z")
> [@fpradelli94](#):
>
> Might it be a problem related to my VPN? I am using a VPN to connect with the office network. In the office used to work fine.
Are you able to ping through the VPN ? To connect using ssh ?
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### Author:  [@fpradelli94](https://discourse.paraview.org/u/fpradelli94)
#### Post date: [March 13, 2024, 12:04pm UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/13 "2024-03-13T12:04:22Z")
@mwestphal Yep, I actually run `pvserver` using `ssh` so the server is reachable.
I even get “client connected” when I start the connection and the RAM of the server is visible on the GUI (the bar in the lower-right), so it looks like something is working.
Still, it sticks to “Waiting for connection to sever”.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [March 13, 2024, 12:06pm UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/14 "2024-03-13T12:06:18Z")
I’m afraid I’m unable to reproduce your issue, you will need to identify the cause of the issue which must be network related somehow.
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### Author:  [@theodorebaltis](https://discourse.paraview.org/u/theodorebaltis)
#### Post date: [March 13, 2024, 4:35pm UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/15 "2024-03-13T16:35:31Z")
I’ve also experienced some inconsistent behavior with 5.12.0 when trying to connect (Windows 11 client and EL7 Linux server). For me, on the client side the pipeline “builtin:” icon changes to indicate a connection but the connection dialog doesn’t disappear. On the server side I get the “client connected” message but then it says “connection refused” after.
Usually just killing the processes and trying again has worked fine.
It’s been so inconsistent that I had chalked it up to some kind of “me issue”, but figured I would share since I saw this post.
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### Author:  [@sherin.sugathan](https://discourse.paraview.org/u/sherin.sugathan)
#### Post date: [May 20, 2024, 9:33pm UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/17 "2024-05-20T21:33:41Z")
Hi @mwestphal
According to @fpradelli94, the connection is established and the RAM status is also showing.
The user is not able to use paraview because the dialog is not closing. Note that the dialog is actually not waiting for the connection to establish. Since he is using an HPC, there is a chance that he gets a message that says “Display is not accessible on the server side. Remote rendering will be disabled.”. The message is a warning box according to the paraview source.
A **problem** arises to the user because warning box will appear behind the modal connection dialog window. The **situation** is that the dialog window is not frozen but just waiting for the user to acknowledge the hidden warning message box. The **solution** is to make those warning messages appear on top of the modal connection dialog window in ubuntu based distributions.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [May 21, 2024, 7:13am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/18 "2024-05-21T07:13:50Z")
Interesting, If I understand well the user can just click on the dialog and then click ok to “fix” the issue, is that correct ?
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### Author:  [@sherin.sugathan](https://discourse.paraview.org/u/sherin.sugathan)
#### Post date: [May 21, 2024, 8:51am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/19 "2024-05-21T08:51:06Z")
Yes, that is correct but doing so is tricky and most users will not see that there is background message… I did some more testing. When this issue happens, one has to resize the connection dialog box to minimum and then you will see 5% of the background message window. I had to try several clicks on the corner of the window to close the background. After closing the background message, then I am able to interact and close the connection message dialog.
Sometimes, you don’t get this issue, because in my observation, the connection message closes before the warning message dialog appears.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [May 21, 2024, 8:52am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/20 "2024-05-21T08:52:42Z")
> [@sherin.sugathan](#):
>
> the connection message closes before the warning message dialog appears.
I finally understand the problem now. Yes. this is an issue and it should be fixed.
Please open an issue on [https://gitlab.kitware.com/paraview/paraview/-/issues](https://gitlab.kitware.com/paraview/paraview/-/issues)
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### Author:  [@sherin.sugathan](https://discourse.paraview.org/u/sherin.sugathan)
#### Post date: [May 21, 2024, 9:08am UTC](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110/21 "2024-05-21T09:08:53Z")
I have raised an issue. Thank you for making things better! ParaView is a great tool because of people like you!
[Next page](https://discourse.paraview.org/t/unable-to-connect-to-server-with-paraview-5-12/14110.md?page=2)