# WebSocket problem after upgrade

**URL:** <https://forum.mattermost.com/t/websocket-problem-after-upgrade/19257>\
**Category:** Troubleshooting\
**Created:** [August 13, 2024, 7:04am UTC](https://forum.mattermost.com/t/websocket-problem-after-upgrade/19257 "2024-08-13T07:04:10Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![cube](https://avatars.discourse-cdn.com/v4/letter/c/9fc348/32.png) [@cube](https://forum.mattermost.com/u/cube)\
**Post date:** [August 13, 2024, 7:04am UTC](https://forum.mattermost.com/t/websocket-problem-after-upgrade/19257/1 "2024-08-13T07:04:10Z")

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Hi,

I have upgraded from version 7.7 to 9.10. The upgrade procedure went without problems, but currently I’m dealing with a problem with WebSocket - on top I have a monit:  
" Please check connection, Mattermost unreachable. If issue persists, ask administrator to check WebSocket"

The Mattermost itself works correctly, I can browse teams and channels, post new messages etc.

My Mattermost is self hosted on Ubuntu 20.04.6 LTS, using Nginx as proxy server.

Befor the upgrade there were no problems like that. What might be the reason?

Any help appreciated.

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**Author:** ![agnivade](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mattermost.com/agnivade/32/3846_2.png) [@agnivade](https://forum.mattermost.com/u/agnivade)\
**Post date:** [August 13, 2024, 7:51am UTC](https://forum.mattermost.com/t/websocket-problem-after-upgrade/19257/2 "2024-08-13T07:51:42Z")

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What is the value of `ServiceSettings.AllowCorsFrom`? You might want to set that to the list of domains from which you are accessing Mattermost.

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**Author:** ![cube](https://avatars.discourse-cdn.com/v4/letter/c/9fc348/32.png) [@cube](https://forum.mattermost.com/u/cube)\
**Post date:** [August 13, 2024, 10:07am UTC](https://forum.mattermost.com/t/websocket-problem-after-upgrade/19257/3 "2024-08-13T10:07:25Z")

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I went to Integrations → CORS and the line “Enable cross-origin requests from:” was empty. I filled it with wiildcar “\*” and the problems is solved.  
Thank you @agnivade

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**Author:** ![agnivade](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mattermost.com/agnivade/32/3846_2.png) [@agnivade](https://forum.mattermost.com/u/agnivade)\
**Post date:** [August 13, 2024, 2:29pm UTC](https://forum.mattermost.com/t/websocket-problem-after-upgrade/19257/4 "2024-08-13T14:29:46Z")

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You’re welcome. Just a note that ideally, you should only set the URLs from which you want access. Otherwise anybody can open WS connection to your server.