My wired headphones are not working

Are you using an adapter? Or do you have a headset with a lighting cable? If the former, the adapters, especially if they are not from Apple, tend to go bad. In either case, try cleaning out your lightning port. Under a strong light, with a magnifier if you have one, use a non-conductive tool such as a toothpick to carefully remove any pocket lint or other debris that might have gotten jammed into the back of the port.

Did you try to Force restart your iPhone first

Force restart iPhone – Apple Support

Do you have another wired headphones to try to see if it's the lightning port?

If your headphones don't work with your iPhone or iPad – Apple Support