Hi Mohamed,
Why do you think it is a firewall issue? Do you see relevant traffic getting dropped by ASA?
Please go through the below guide and see the ports and protocols that should be allowed.
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/jabber/10_5/CJAB_BK_D6497E98_00_deployment-installation-guide-ciscojabber/CJAB_BK_D6497E98_00_deployment-installation-guide-ciscojabber_chapter_011.html#CJAB_RF_N0DB4182_00
Hope this helps!
Regards,
Kanwal
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