I searched the forum and looked for other incidents of this problem, but none of the solutions I found there worked.
(There’s an RTP timeout setting, and an event passthrough to SDP setting somewhere else.)
I did a packet capture, hopefully that will give one of you a clue as to what’s going on. I had to break it into two pieces and zip it up to meet the file size restrictions for attachments.
Any help will be greatly appreciated, as always!