2017 Forester backup warning beep stopped working

What is your question?

My 2017 backup warning beep suddenly stopped working all the time, and only works randomly - more not than often. Does anyone know how to fix this? Don't know what more extra detail to add - I could go through a fence and the beep wouldn't go off. It does work at times, but I can't rely on it. It used to work all the time. I tried cleaning what appears to be a camera around the license plate area, but it did not help.

How long has your 2017 Subaru Forester had this problem?

About a month