Grey checkered live view

Hi there. I’m very new to SS5. Yesterday, I was able to connect both of my canon cameras with live view. Today I’m trying to connect just the Canon Mark IV and I’m only getting a grey checkered background in the live view. I have live view enabled and set to the Mark IV. And when I click the enable, I hear the mirror flip in the camera, so I know it’s connected. In the cameras tab, the Mark IV says Ready. Any idea what the issue is?
~Heidi