I am new in Issabel and SIP world, so I don't know how to fix this problem.
I have entered IP block such as 192.168.XX.XX IP address on Issabel Gui via System->Network->DHCP Server and saved it. After that, I tried to delete this IP block but it didn't allowed me to make it blank so I click on Disable DHCP. Eventhough I disabled it, my SIP phones who has IP address starts with 172.34.XX.XX is not working and Issabel doesn't reply their Register messages. Only phones who has IP address starts with 192.168.XX.XX was working. After I reinstall Issabel, my problem is solved and both 192.168 and 172.34 phones working fine.
Could you please solve me this problem?