Smuxi

When connecting to the remote engine, I receive the following message:

(The port number may vary as it is your personal setup)

This error is thrown cause you've been recently connected to the engine or tried unsuccessfully to connect leaving an old SSH connection behind, which is blocking Smuxi from connecting to the engine.

There are two ways to handle this error:
1) Wait a while (maximum 2 minutes) then the old SSH tunnel is killed by itself
2)
Linux:
Look in the System monitor for ssh or use the ps command to kill that process and try again.

If it doesn't work cause the remote ssh tunnel is still active:
Connect to the server on which the remote engine is placed:
type the command

ps x

You will receive output like the following:

  PID TTY      STAT   TIME COMMAND
28764 ?        Sl     1:45 mono /usr/lib/smuxi/smuxi-server.exe   <--------- Smuxi server
27239 ?        S      0:00 sshd: heavy                            <--------- SSH-tunnel
31675 ?        S      0:00 sshd: heavy@pts/2                      <--------- current terminal session on the server
31677 pts/2    Ss     0:00 -bash
31698 pts/2    R+     0:00 ps x

Type in the command kill <PID> (in this case it would be 27239 so I would have to use kill 27239) to kill the SSH tunnel.
Connect with Smuxi like usually.

Windows:
Use the task manager to kill the following process: plink.exe