External Phones Not Completing Calls

I have a FreePBX server. All packages are updated and we are using PJSIP for extensions.

Internal phones have no problem connecting to the server and receiving and making external calls.

External phones such as a Yealink T28P and Bria Softphone can register just fine with the server, but after the first ring when making a call it stops ringing on the extension, continues to ring on the external device(cell phone) and when I terminate the call it stops ringing on the External device.

At first I thought this was a Verizon SIP ALG issue on the Bria phone, but when I tried this on the Yealink at my home office, and removed all firewall (not the responsive firewall) rules to make sure there were no port issues. Still no success.

I have heard this might be due to some issues in the PJSIP stack. Any thoughts?

Some back story, we had these working before just fine, we had the server set for PJSIP and then changed all extensions to SIP to try and get the ZOHO Phonebridge to work, after we gave up on that we changed extensions back to PJSIP.

Bump on this question.