fob receiver not working?

Hello,

The first thing you need to make sure that the battery in the fob is good.
Overtime those battery will deplete and will need replacement.

If after a new battery the fob still does not work, it could either need to be programmed or the fob is faulty.
Another possibility is a bad keyless module that is in the vehicle.

Here is helpful guide on key fob programming:

https://www.2carpros.com/articles/how-to-re-program-a-key-remote-fob

Please let me know if you have any questions.
Thank you.