Delayed starting and move sounds

Hi all.
When I play on my phone (Firefox for Android), the starting sound of the game sometimes is delayed. As long as it doesn't play, there are also no move sounds. Most of the time, the sound appears like 5 moves deep into the blitz game, sometimes already at move two, but rarely and the beginning of the game, as it should be.

I remember that I've had this on my computer as well (quite some time ago already), but I don't know whether I did anything to fix this myself, or whether it got repaired for me.
Best!

On the desktop version of Firefox, audio is automatically blocked until you give the site permission to auto-play audio (Press ctrl + i to access permissions). I'm not sure about the mobile version, although I assume that the same thing is happening.

I've tried this (took me a while to find the corresponding option on mobile), but this does not do anything.

I can't fix it... Any help?? On Android app it just keeps having the delay.