WebSocket connection error

On self-deployed installation we receive the following error on Chrome console:
WebSocket connection to ‘wss://DOMANE_NAME/socket.io/?dtable_uuid=0b123a88-d526-405f-9aab-165b58d0601d&lang=en&EIO=3&transport=websocket&sid=giD2E4xfjOaf9iaHAAAG’ failed:
f.doOpen @ websocket.js:112
a.open @ transport.js:84
c.probe @ socket.js:370
c.onOpen @ socket.js:391
c.onHandshake @ socket.js:446
c.onPacket @ socket.js:411
(anonymous) @ socket.js:257
r.emit @ index.js:135
a.onPacket @ transport.js:147
(anonymous) @ polling.js:141
t.decodePayload @ browser.js:400
c.onData @ polling.js:145
(anonymous) @ polling-xhr.js:129
r.emit @ index.js:135
d.onData @ polling-xhr.js:299
d.onLoad @ polling-xhr.js:363
hasXDR.t.onreadystatechange @ polling-xhr.js:254

Seatable works, but it crashes randomly. The problem is that before freezing, it actually doesnt save data, so the user is not sure which data were saved and which not. We have only one base, still preparing tables etc. what could be wrong?

Please provide additional information:

  • which version?
  • which environment?
  • did you follow the official manual or hardware recommendations?

Version 4.2.11
we followed the hardware/system recommendations.