No sound in sim but working in main menu

Hi there,
today I noticed that there is no sound at all when entering a race session (practice, qualification, race, doesn't matter). However when in the main menu the music and sfx are there. Also checked my settings but everything is set up correctly. Tried different cars and tracks, with headphones, without headphones, nothing changes.

 

EDIT: please delete, it is working again.

 

For future reference, any idea what the cause was?