Same problem here.
Funny thing is, that for some users it works fine, but for others they can’t play the recordings. I think it’s some Windows 10 thing. I’m running Framework 14.0.16.4 and UCP 14.0.3.18. It’s the case with any and every browser. On one Windows 10 it works, on another it doesn’t.
If I check the error console in the browser whilst the recording plays and fails, I see:
HTTP “Content-Type” of “text/html” is not supported. Load of media resource about:blank failed.
It looks like the streaming is failing.
So, the voicemail that plays is on Windows 10 Pro 1909, and it’s not working on Windows 10 Pro 20H2.
Here’s another related thread: User Portal Voicemail Will Not Play
(I know, I know, I need to update… and I will, but I have to plan the time for it…)