Grinding noise and sensor alarm first thing in the AM

Hi! New to the forum and looking for suggestions. I bought a 2021 Rogue Sport S 6 months ago. For the past 2 mornings, I've put the car in reverse and the sensor alarms and the collision light comes on in red and there is a terrible grinding noise from what sounds like the back end of the car. I'm nowhere near hitting anything. A friend suggested I'm not letting the engine light go off before throwing it into reverse. Any ideas?

Thanks!