Cannot access CQ5 Author instance via http://HOSTNAME:4502 , only by http://IP:4502 - DNS Working

Cannot access CQ5 Author instance via http://HOSTNAME:4502 , only by http://IP:4502 - DNS Working

MY dns is working but still for some reason i cannot pull up the instance via hostname only via IP address. Is there something in CQ i have to do to make this work?

Thanks