[howi42]

I am running a server on one system. ( 5.3 )
If I am using the client on the same system, everything is fine.
If I shut down that client, leaving the server up and running, I cannot connect to the database by running calibre on another system.
If I shut down the server, too, I can run calibre on another system and connect to the existing databases.

I had never problems before running the server on one system and run calibre on another system.