i tried my first debian client after several windows systems. But urbackupclientctl status says just
i configured settings as it should be
but when running urbackupclientbackend
i get the following statement
2017-04-15 10:57:07: ERROR: urbackupserver: Failed binding socket to port 35623. Another instance of this application may already be active and bound to this port.
I got the same error message. I assume it just means that we tried to start the server again, which is already running. I ignored it and the server was able to find the client, after I had disabled the firewall on Debian (Linux Mint in my case). Finally I configured the firewall with the port given in the UrBackup administrators manuel and everything was fine.