The headphone jack is shown with a red ring.

Wear a grounding band or at least ground yourself before proceeding.

Apply gentle pressure to the 2 areas marked in blue with your finger.

This pressure slightly flexes the area and may cause poorly soldered pins to re contact.

If the sound returns and the red light turns off the issue is likely caused by a poor solder connection on the board. If not this fix may not work for you.