All target frames are completely opaque (Content-Aware Fill)

[#1]

As titled suggests, can't figure it out - Please help! 

[#2]

As titled suggests, can't figure it out - Please help! 

[#3 · Accepted solution]

It's because i had a white background... silly me. sorry for wasting time.

[#4]

This wasn't a waste of time at all! I was stuck and couldn't figure out why CAF wouldn't work. You posting this helped me figure out exactly what my issue was.

Cheers!

[#5]

I dont have a white background and still getting this. Should there be a layer under the layer with the mask?

[#6]

I have this problem as well.  Did you ever find a solution?

I have 1 layer, two masks set to subtract.  Couldn't be simpler, I would have thought.

..but it just comes up with the message that All Target Frames Are Blank and it aborts the fill layer generation.