V18.3 - Incoming call answered but caller just hears ring tone

I’ve just started using a number provider who passes all calls directly to my server via SIP without any authorisation.

I receive the call on my Asterisk box (pjsip) and process it using the number dialled as the incoming call id. Extensions etc ring as required and the voicemail routines activate as they should.

But the caller just hears ringing on their phone despite the 1st line of the dial plan being answer()

Other trunks which require authorisation work perfectly.

What am I missing? I’m sure it’s obvious but I’m blowed if I can spot my error.

TIA

Double check the output of pjsip set logger on, to make sure 200 OK is actually sent. If it is, the problem is upstream.

is this happening on the same context (for old trunks and new one) ?
if not then it must be a typo in the new context part of the dialplan, check it out and check for errors in the console.
if it is the same context then your new provider is actually providing a fake ring on his inbound leg and on his outbound leg to you he is not capable of communicating with your server correctly (could be codec issue ? missing sdp ? firewall ? )

Thanks guys. It’s looking like it’s upstream. I’ll do some more work on this next week as I’ve got a couple of vacation days