Proxy Errors with MM Installation on Webmin with Apache

We installed mattermost on a webmin installation to share the hardware with multiple webapps. It uses apache my default and we have it running but it constantly throws up the banner that the server is unreachable.

Observed behavior
We get the following error in the browser: Please check connection, Mattermost unreachable. If issue persists, ask administrator to check WebSocket port

We are not versed in apache, websockets, reverse proxying in general… in the logs I see these three errors repeatedly but I am not sure what to look for or how to resolve.

I’ve clipped the timestamps and PIDs, etc.
AH01084: pass request body failed to (
AH01097: pass request body failed to ( from {MY TESTING IP ADDRESS} ()
AH00898: Error during SSL Handshake with remote server returned by /api/v4/websocket