Thanks for the help mc_
The hangup cause always looks the same.
There's two lines, the first one shows from my number to theirs with a duration of 13 seconds and the hangup cause is "normal clearing"
The second line shows from my number to their user name (I think, it's user_A9rrcb98Qm), the extension name and then a phone icon and their actual extension of 365. That shows a duration of 5 seconds and the hangup cause is "recovery on timer expire)
When I read this earlier I was wondering if the hangup cause had anything to do with the issue or not since I just terminated the call rather than leave a message. I can always pull up the technical details associated with each line if there's something in there you think I should poke around for.