This might be the wrong location,

I have setup HASS on an RPI3, and all was working… until the last few weeks I have started to notice SSH, and SMB stop working but still being able to access the HASS URL, automation, etc. find.

message when trying to SSH Connection closed by ... port 22

Does anyone know the best way for me to Diagnose the problem

First thought: attach a monitor + keyboard to find out what the problem is. Besides SSH there probably is no other option to connect remotely and get a shell to work with.

You can use:

ssh -vvv user@server

to troubleshoot your ssh connection

Cheers for you help guys; I have now moved the DB onto my NAS ( MYSQL). For the last 24hrs, all seems to be OK and, I can still SSH, etc… :wink: