The network connection works, but logging in using https is still not proven (or you haven't said so).
Try connecting with a web browser to https://hostname-ilo and log in using the username and password used with fence_ilo. Does it work?
What's your hardware model, iLO firmware version and RedHat version?
If you have one of the latest server models and an old version of RHEL, the fence_ilo version might be too old to support your hardware.
In this thread, Reiner Rottmann offers a link to an alternate iLO fencing agent:
http://h30499.www3.hp.com/t5/System-Administration/fence-ilo-repace/m-p/4756390#M43700
Might be worth a try.
MK