I cannot find the correct instance/DB name to use to connect to a database.

UNIX server name is "financeserver"  I believe the INFORMIX database name is "CITY-1459745C48 and database is Encompass"   I have the instance/DB as "CITY-1459745C48/Encompass"   The server connection to financeserver is connecting. I am unfamiliar with UNIX and INFORMIX to determine the correct INFORMIX server name.  Can anyone help with this?

thanks!!!!!!