IIS issue WebSocket

[S72TM]

Hi,
I need some help, project it working without problem on my computer. Problem is, when I publish on IIS, I receive below error in browser and app stop working, only if I restart the pool again is working for few seconds.
Project is started in mudblazor but from error I guess that is releated to blazor.js

blazor.server.js:1 [2024-03-12T22:07:52.254Z] Warning: Failed to connect via WebSockets, using the Long Polling fallback transport. This may be due to a VPN or proxy blocking the connection. To troubleshoot this, visit https://aka.ms/blazor-server-using-fallback-long-polling.

Any ideea where is the problem and how can be fixed ?

Thanks in advance !