Audacity 3.2.1 - macOS Monterey - Version 12.5.1
I’ve been using Audacity for a few days to record an audiobook and didn’t have any issues.
The “low battery - plug in computer” notice came up on my screen today, and I clicked out of it. Since then, audacity has stopped playing its audio out loud.
Not sure if it’s related to the low battery notice or just an extreme coincidence.
The waves are blue like usual, and the playback meter shows normal movement however I can’t hear the audio.
I have tried all the general suggestions for when this happens. Double checked my built-in speakers are selected for output in audio setup, restarted my mac, uninstalled audacity and installed again.
This issue is for the whole of audacity, not just new recordings, old files also have this issue when I try to play them through audacity.
Please help! 
Not sure if it’s related to the low battery notice or just an extreme coincidence.
So you plugged your machine into “shore power” and what happened?
The volume control buttons on my keyboard make “poit, poit, poit, poit” sounds when I change the volume. This is independent of a show, production, or sound connections. This can be a super handy diagnostic if you start having troubles.
Did your used to make those noises and does it still?
Koz
I’ve been using Audacity for a few days to record an audiobook
First book?
You can submit a short sound test here on the forum and we can, many times, catch audiobook problems before they build into days of work. The makers of home microphones make this sound a lot easier than it is.
https://www.kozco.com/tech/audacity/TestClip/Record_A_Clip.html
This is, of course, after you get the machine back up.
Do you hope to be submitting to Audible/ACX? They have two pre-production notes to consider. Your work must be for sale on Amazon (no option), and your work can’t can’t be on this list. (scroll down).
https://www.acx.com/help/200878270
You can’t read a cookbook.
Koz