Multicamera View 3/4 cameras now show as black screen

[defaultl161ha7cdos1]

I edited a multicamera wedding ceremony shoot last week and I came back to the project this week and 3 out of 4 of the camera angles are black. The cuts are all still there and as you can see in the screenshot, the angles I selected are still shown throughout, however every camera angle but one have seem to disappeared. I'm new to using Premiere Pro's multicamera editor, so this may be something very obvious, but I don't know what happened or how to restore it. 

Computer Specs:

 

Thank you in advance for any help! 

[gerikp]

Have you tried deleting your cache and restarting Premiere Pro?