Same "Video not playable" issue here. No such issue when running ZM 1.30.4.
Zoneminder 1.32.3
Phone is running Android 7.0 (last patch date April 1, 2018): it's an unlocked phone (basic kernel).
Basic/relevant log info (reversed log output listing to make a top-down sequential read):
DEBUG Player is ready
DEBUG *** Invoking play
DEBUG neighbors of 112are pre=111 next=
INFO >>>Starting checkAllEvents interval...
DEBUG player reported a video error:{"isTrusted":true}
INTERESTINGLY, I do NOT have this issue on my wife's phone, which is running Android 8.1.0 (last patch date Oct 1, 2018).
No issues running 1.32.3 under Firefox (Linux mint) on three different laptops (one even running Windows 10).
BUT, via Firefox on my phone I get the error "The video was aborted due to a corruption problem or because the video used features your browser did not support."
Looks like and Android version issue?
I wish that I'd stayed with 1.30.4. I only went for the upgrade after toasting my server.