Left Earbud not playing music even when connected

Hi

Now sorted - was a setting on my Mac had been changed! Thanks

My left earbud has stopped playing music when the right one is still working. I have reset them by pressing the button for 10 secs and re-establishing a new connection. They have been fully charged overnight.

Strangely, when I first connect they both work and I can hear the word' connected' in the left earbud, but when I come to play music from any source it only plays in the right earbud.

Thanks for your help