Have them check the camera cable, it seems like it naught be loose? The simple has to mean no camera detected .
I just experience this same issue. I will have to take this back to dealership if it continues. Just purchased 1 month ago.I just purchased a 2023 Trailblazer RS last week Thursday. Everything was great, drove to my office the next morning, went to leave and the backup camera was not working. All I get is a black screen with the "warning" triangle (triangle with exclamation point in the center) and a camera crossed out. Took it to the dealership last night and of course when they went to pull it into the shop, it was working. Worked when I left the dealer and when I went to back out of my garage this morning, it's not working again. Anyone else with this issue and was able to get it resolved?