Apple Earpods suddenly too quiet while playing music

Hi together,
I own an Fairphone 4 5G and recently bought Apple Earpods. At first, everything worked fine. But from one day to the other, when playing music/podcasts, etc. the sound is very quiet - even though its on the maximum level. Its weird, because when i make calls, the volume is still very high. I restarted my phone but it didnt help. Anyone had a similar problem and could solve it?
Thanks in advance!