I used Sangoma’s nifty migration instructions here:
Upgrading+from+FreePBX+10.13.66+to+SNG7 (Sorry, can’t link to post, google it.)
and got everything mostly working on a fresh machine. However, fm/fm would not successfully dial external numbers and was inserting an alert-info: header into any outgoing FM/FM call that originally entered the system though our IVR from the trunk (not internal extensions).
The bug looked pretty close to issue FREEPBX-17927 in the bug tracker.
After beating my head against the wall for a couple hours, I checked my time conditions module. The “alert-info” section was set to “none” HOWEVER…
When I used the Sangoma migration script to transfer over from our homebrew distro to SNG7, the script seems to have created on the Inbound routes page an alert info of “none.” This shows up in the dropdown box as a second none after the sangoma ring settings, and should not be confused with the “none” at the top of the dropdown box. Changing the dropdown to the top “none” unsets the alert-info from sip headers and enables fm/fm to call external extensions without AT&T rejecting the malformed SIP header.
Much fun that one. I don’t know if it can be reproduced, but I figured this might help someone.