How to fix an Audi A3 key fob that won't lock or unlock the car?

My Audi A3 key fob has stopped working and I can't lock or unlock my car with it. What could be causing this issue and how can I fix it?

First, try replacing the battery in your key fob. If that doesn't work, it could be a problem with the key fob itself. Try reprogramming it or getting a new one.

Check for any potential interference, such as other electronic devices or metal objects, that may be affecting the signal between your key fob and car. Move away from any potential sources of interference to see if that helps.