I am experiencing failed 911 calls when using an Adtran that is interfacing with a 3CX PBX. We use Metaswitch as our phone switch.
Right now what I am seeing is that when a Emergency call is made Metaswitch is giving a 403 From URI not recognized. I thought this was due to the way the Adtran was sending the ANI for this particular DN. But after doing a Caller-ID-override Emergency-outbound for the ISDN trunk nothing changed and continued to get the same 403 from Metaswitch.
When looking at this call the URI for the Emergency call has the from URI shown like 1XXXXXXXXXX and I believe that the added 1 in front of the 10 digit DN is what is causing the 403 From URI not recognized.
Does anyone have experience with Emergency calls with Adtran as to what I can do to fix this?