Hi @Farook,
The error you’re getting means that there are issues with the websocket connections - can you help take a look at our troubleshooting tips here for help:
- https://docs.mattermost.com/install/troubleshooting.html#please-check-connection-mattermost-unreachable-if-issue-persists-ask-administrator-to-check-websocket-port
- https://docs.mattermost.com/install/troubleshooting.html#failed-to-upgrade-websocket-connection
- https://docs.mattermost.com/install/troubleshooting.html#websocket-closed-or-websocket-re-established-connection