If your audio player in Moodle lis just a black rectangle with no controls and you can not play the audio, then you probably have a “double filtering” problem. This happens when both the Poodll filter and the multi media plugins(MMP) filter in Moodle don’t cooperate. Basically, Poodll swaps out the audio file link with an audio player. Then MMP sees the audio file url in the audio player, and again tries to make a player out of it. This produces an unworkable mess.

The solution is any of these four:

i) Turn off (disable) the multi media plugins filter at:
site admin -> plugins->filters -> manage filters
If you do this be sure that Poodll is handling all the media files that you need, probably MP4, MP3 and Youtube.

OR

ii) Leave MMP in place, and have Poodll just “cachebust” the media files, and pass them on to multi media plugins to play
See: https://poodll.com/poodll-3-docs/how-to-use-poodll-and-the-standard-moodle-players/

OR

iii)Leave MMP in place, and just remove the “.mp3” and “.mp4” (and maybe Youtube) from the extensions handled by multimediaplugins:videojs. Then Poodll will play those exclusively.
Do that at: site admin->plugins->media players->videojs player

OR

iv) In Poodll Filter 3.0.51 (Build 2017081101) and higher we use  different technique to make sure the two filters do not clash. If you upgrade to the latest Poodll filter AND update the player templates you are using to the latest in those versions, then simply having Poodll higher than MMP in the list of filters will be enough. See here for how to update your existing player template to a higher one after upgrading Poodll.
https://poodll.com/poodll-3-docs/how-to-update-a-template/