Apple Music not working on iPad?

Hi, the following problem:

My mother recently wanted to listen to Apple Music on her iPad. But it wouldn't work. The song would start, but there was no sound. So she asked me for help. I checked to see if she needed to update Apple Music, but the app was up to date. Everything was fine in the settings, too. The sound works in other apps. She can't listen to music through speakers or headphones either. There's no sound for any song.
What's causing this? And how can I fix it?

Thanks in advance 🙂