1858: the connection with the remote management agent has timed out

I get the above error when trying to remote control a specific workstation.

Both WS has the same client installed and same ZEN and remote agent. Both
remote agents are started.

I have removed and imported the WS object a couple of times but it doesn't
help either.

The "master" WS is able to remote control other workstations.

Anyone have any idea?