Spark 2.5.5 + Mac OSX not connecting

I am evaluating Openfire/Spark as a collaboration tool. It appears to work just fine for our Windows testers, but our lone Mac tester is having problems. He tries to connect to the server and it timesout. He is a registered user in Openfire. Has anyone had a similar problem or know if the Mac itself is blocking the call.

TIA,

Greg Piney

Is the OS X firewall turned on. If it is you will not be prompted to allow Spark. The firewall will need to be configured to allow spark to communicate.