UCA Mobile Softphone Not recieving calls

[Frankiev]

I have a client that we setup UCA and have all the licensing needed. It is connected to a Mitel 5000 ver 6.0.120.0
 Mas version is 5.0.116.0 and MSL version is 10.0.43. The issue they are experiencing is the softphone connects and they are able to make calls using the softphone but they are unable to receive calls. If you try calling the SIP extension, the pone locks up for a minute trying to call the phone and the your get destination not responding message. I have all the ports opened according to the engineering guidelines. The customer is using AT&T as a carrier and are using Iphones.

Any help is appreciated.

[martyn]

If you run the TNA against the pulbic IP address of the MAS does it show that the correct ports are open and listening?

[Frankiev]

The UCA client works fine. I am able to chat, change statuses, etc. It is just the softphone that has the issue. I have the forwarding between the UCA and Phone system occurring at the firewall as this is what was described in the engineering guidelines for a Mitel 5000 setup.