In my case, I was messing around with UDP sockets and intentionally connected to a port from a different app. Then tried to connect to that same port through UE5 and it threw the same exception.
So out of curiosity, I googled and found this post. As @Ari_Epic mentioned:
it adds up with my scenario.
So I suggest you do check for the same (if any other app is listening to the same port).
and you can find that from cmd:
netstat -ano | findstr <port_no>
it would give you the process id (i.e. 4932)
and you can kill it with
tskill <PID>
Hope it helps 