Some of our users are experiencing problems with Callcentric as a voip provider. Trying to troubleshoot the problem, I noticed under wireshark that a great amount of "407" are returned in response to our REGISTER. The client might be able to connect on the first try, but sometimes, one have to repeat the action quite a few times before succeeding. In those cases, pjsip returns: "Maximum number of stale retries exceeded (PJSIP_EAUTHSTALECOUNT)" in our pjsip_regc_cb. I tried to set the expire value to PJSIP_REGC_EXPIRATION_NOT_SPECIFIED as recommended (expire not set) on their support page but this change had no effect. How should we tackle this problem ? What might cause the PBX to return 407 all the time, considering that the authentication information is valid, and that it succeeds registering say 2/3 of the time.
