Need to fix "Park Assist Blocked" error message

What is your question?

For more than a year the rearview camera on my 2011 Chevrolet Texas Edition Avalanche hasn't worked. Periodically, I will see messages pop up that say, "Park Assist Off," or "Park Assist Blocked." Most of the time the backup beeping still works

What makes this problem better or worse?

Nothing apparent

How long has your 2011 Chevrolet Avalanche had this problem?

Over a year