Adele -- Hello ... Where'd My Audio Go?

Adele's Grammy performance Monday night should have been the highlight of the show ... but the sound engineer had different ideas.

The singer took the stage towards the end of the night to perform "All I Ask," but her mic cut out early in the song and the audio took a little bit before finally recovering.

You had one job, sound guy ...

BTW -- the whole song seemed a little ... off.