2021 Tesla's rear-view camera and collision warning systems did not activate when backing out of a parking spot. Tesla screen showed the navigation map instead of the rear-view camera while I was backing out at low speed ~2 mph. A 2003 Honda Pilot directly behind me was also backing up at the same time resulting in a collision. After the crash, I confirmed that all safety features were enabled and I have always installed all regularly scheduled updates. After searching online forums, I found many customers reporting problems with their on-screen camera not activating. I have noticed that the camera did not consistently activate in the past. Sometimes it would, other times I would have to manually press the Camera button on-screen in order to view behind me. There were no on-screen notifications of problems before the event. However, there was one notable change I made to re-enable Sentry Mode (security) after being disabled for some time. Prior to the event, I was notified that two Sentry Camera events were available to watch but they would not load when I touched on screen. After the crash, I discovered after the crash that both Sentry and Dash Cam were not working so there was no footage at all of the crash! Nor were these Sentry events visible. This leads me to believe there is a bug with the camera system.