Maximum retries exceeded on transmission

http://bugs.digium.com/view.php?id=5336

This is not a problem with Asterisk - essentially what happens when you cancel a call is this:

1. Phone sends CANCEL
2. Asterisk sends 487 Request Terminated
3. Asterisk sends 200 OK
4. Phone sends ACK to acknowledge the above messages.

Your phone/device is not sending an ACK back, so Asterisk continues to send the 487 Request Terminated because it knows no better.

This is a problem with SIP non-compliance by the phone/device, specifically, rfc3261, section 17.1.1 requries an ACK to the 487. If Asterisk do not get ACK'd, it should resend.

Solution

If you are using some softphone - try to change it.

If you are using some hard-phone - try to upgrade/downgrade firmware.