Audio stops when screen auto-locks/sleeps

If I play audio then press the lock button myself it will play then I go about my business. Then When I have to pause for more than the 5 mins I have auto-lock set, then it won’t play again. I have to stop what I’m doing, go over to my phone, unlock it and then it will play.

this defeats the purpose of having a pause play button if I have to go back to my phone. It’s not feasible to leave my phone on never lock. Makes it inconvenient when I’m doing manual labour.

This is for an audiobook app. i would appreciate a fix for this if someone has.

Thanks