Another client is connected

Naturally we want to prevent, that two clients at the same time get control over the microscope, so we allow only one client at a time. So check all the environment to see if anybody else is using the microscope. This may even be a stack running in the background (see Sec. 2.11). You may want to switch over to the server computer (see Sec. 6.6.1 and see if sm_server is currently listening for a new client or not. You may kill and restart it, but should make sure, that you don't ruin somebody else's work by doing this.