Folding key is failing

Hello! I'm having a problem with my key fob (3 buttons) for my Passat (year 2001). It seems to be weakening, meaning I can no longer unlock the doors remotely from at least 10 meters away.
Now, however, it only goes for a maximum of 2 meters beforehand.

What could be the reason ?

I have already changed the battery .

Maybe one of you has experienced the same problem before and can tell me what caused it.

It must be something wrong with the key because the other spare key works perfectly fine.

Thank you very much .

Hello,

It most likely has to do with a broken connection. These things sometimes fall and get damaged, you know? Reflow the solder joints and it should work again! It has always helped me.

Best, Sascha.