Content aware fill not working

I know I'm late but I've been having the exact same problem and don't know how to fix it: Did you get the solution to your problem?

It doesn't look like you've used a reference frame (apologies if you have and I'm missing it), typically with content-aware fill the more info you have give AE the better.   In this case a reference frame could be used by AE to help fill in the blank space.

Edited to say - you can then bring this into Photoshop and fill in the space, then back in AE the software can use the still as a guide (or reference)

That is a huge hole to fill. You are going to have to create a fill using Photoshop. Have you gone through the user guide on content-aware fill? Photoshop couldn't fill that hole automatically. There is just not enough surrounding information.

Have you tried viewing the created Fill Layer in the Layer Panel? Does it look OK there? Have you checked the Fill Layer's Transform properties to ensure nothing untoward has been introduced? I just noticed your plate is a 3D layer. Is there a reason that it's a 3D layer? What happens if you set it to 2D and re-apply CAF and follow this with a Nesting routine and then turn the nested comp into a 3D layer; does this create expected results with a more refined and structured workflow?