Remote Key stopped working

[AzNMpower32]

A couple days ago, the X3 stopped locking/unlocking remotely. Neither of the keys will work, although they both function normally if you stick the key into the hole and un/lock manually. There are no other side effects.

I have an appointment with the dealer to check it out next week, but today I happened to stop by Autozone and they had a remote receiver that allowed you to see if your remote was working. My remote works fine; I think something is wrong with the car that doesn't allow it to receive the keyfob commands.

Both me and the service advisor have attempted to reinitialise the keys to no avail.

Any fix? Will I have to replace the entire inside rearview mirror (which houses the antenna)?