Frequent Connection closed says Putty

[duceduc]

I have a rpi4 (Buster) setup as headless. I use putty to login. The only app I install is Plex Media Server. Every so often Putty says 'Connection to (local ip) closed' when I try to login to the server. The rpi seems to be running as I can still access my Plex Media server. I cannot ssh into the pi, however. Force unplugging the pi brings it back, but after a few days or so, the connection is closed again.

A little more info. I can login via putty, but once I start typing something, the putty screen closes immediately. If I try to ssh into the rpi4 from another machine. I get a message saying the connection closed.

[duceduc]

I think I figured out the problem. SSH was disabled which I find it weird. I did not disable it as I only connect via putty. I do not have a monitor or keyboard plug in to the pi.

The only thing I can think of as to why ssh was disable is from the several kernel updates we have had within the last month. It may have revert the pi setting back to default and disabled ssh along with it.