Trouble starting Synergy session

Warning provided to user when starting synergy client session:

Duplicate user name: 'john'
Warning: Syntax error(s) in attribute 'users' of base/model/base/1.
Starting in multiple server mode.
Set the environment variable CCM_ADDR to serv:32920:123.321.231.213 to send commands to this server.
SYNERGY/CM address is serv:32920:123.321.231.213.

Solution: run "ccm users" and remove the extra occurence of the problematic user ('john').