I'd put my money on the 3.5mm jack having failed in some way unless the card to front panel cable has become disconnected.
I've seen quite a few of these fail particularly when used with headphones.
They don't seem to be built with sufficient robustness to cope with headphones being plugged in/out regularly.
It could be repairable with a soldering iron if the solder joints have cracked. It can be difficult to source an exact match for the jack if it requires replacement.
Perhaps worth trying the manufacturer for a new front panel connector or a warranty repair ?