I was setting up a remote extension, UA is a softphone running Mac, and there was a strange issue: softphone is registered, Status screen shows extension in green.
However incoming calls land in voicemail. If I disable voicemail it says "Congestion" - even though extension shown as registered.
That sounds like a NAT traversal issue. A couple of questions are:
• Which Mac OsX SIP UA are you referring to?
• Behind which type of router does this UA reside?
• Does the UA support any NAT traversal method? (STUN, ICE, TURN)
Can you try to send a call to that extension, right after it registers? Will the call go through?