Look in settings >developer options and check if "use nuplayer" is ticked. If it is, untick it.
To get into developer options you need to do this first:
Go to the settings menu, and scroll down to "About phone." Tap it.
Scroll down to the bottom again, where you see "Build number."
Tap on build number 7 times.
I have no affiliation whatsoever with O2 or any subsidiary companies. Comments posted are entirely of my own opinion.
This is not Customer Service so we are unable to help with account specific issues.Currently using:
Pixel 7a (O2 & Lyca), One Plus 6 (Sfr), iPhone 12 Pro Max (Vodafone)