Server timeout elapsed without receiving a message from the server

User Binod Kachhapati has sent us the following question:

…the server is responding . we can also login into the system. While we are checking the submitted forms ,suddenly the errors shows as “Server timeout elapsed without receiving a message from the server”. We relogged many time. It’ shows the error

This error is consistent with inability to communicate through web sockets. Refer to Websocket connectivity check.

See also post installation configuration instructions.

In admin section, it shows following message .

Web socket connectivity

[2021-08-03 07:47:40] Building connection to server using `/signalrdiag` url
[2021-08-03 07:48:11] Failed to invoke server method with error: Error: Server timeout elapsed without receiving a message from the server. 

there no ping or pong reply. please help us to fix this issuse.