[AFMUG] SIP Trunks w/ Cisco UC-500

[Keefe John]

We have a customer trying to configuring their UC-500 Phone system with 
our SIP Trunks.  They can't seem to figure it out and we're not UC-500 
experts.  Their system registers to our server but incoming calls get 
dead air for 60 seconds, then ring once,  then an all circuits are busy 
error.  At first they thought it might be NAT related so they setup 1:1 
NAT with wide open firewall rules and it does the same thing.

Any advice would be greatly appreciated!
Thanks,

Keefe