Roaming cell phone can not receive calls 3g

I have an extension that is a cell phone running 3cs & bria (tested both of them). I can register the phone place calls and everything, but as soon as I go to 3g, I can not receive calls. If I am on WIFI It works no problem (my Network is as follows)

CELL PHONE
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/
INTERNET
|
/
FIREWALL 1 with WIFI
|
/
Firewall 2 Internal Network.
*ASTERISK BOX IS ON INTERNAL NETWORK

From the cell phone softphone running on 3g I can make calls anywhere in the internal network just can not receive and it is coming up unavailable. I was changing a lot of settings, does anyone know what setting I may have changed that would produce this behavior. It was working at one point with 1.8 asterisk (FIREWALL HAS NOT CHANGED), but since I upgraded to version 10, I am not sure if it ever worked.

Thanks!!

OK, I found the error for anyone else that experiences this.

two things, first I was using BRIA on IOS to connect to Asterisk, which their stun server does not seem to want to work, so I recommend first to test get 3cs softphone.

on the SPECIFIC roaming extension set NAT = YES
This is in conjunction with in sip.conf you need to setup Nat as well. Once that was done I was able to bypass the stun server that did nto work on bria and the phone now works flawlessly. Make sure if you are using bria to go into settings and set the configure mode to Server Managed as well and then under advanced settings in the profile set SUPPRESS stun mobile.

Hope this helps if anyone else runs into that issue.