Can't connect to workstation using ssh from a remote machine

[Gary Dale]

I'm running Bullseye on an AMD64 system on my workstation and Buster on 
an AMD64 system on my server.

I'm trying to establish an ssh connection from my server to my 
workstation to facilitate a nightly pull backup of /home run by the 
server. However the ssh request times out.

I can connect via ssh to my workstation locally, just not from other 
machines *i.e. ssh <workstation> works when run on <workstation> but not 
when run on a different computer).

Debugging output isn't any help. It shows the connection being attempted 
then eventually timing out.

Any ideas pm what is going on? I've noted that Bullseye seems to have a 
problem with GnuTLS right now (for ftp operations). Could that be related?