Weird Border round camera

Hi there , I originally made a follow camera to emulate a true first person camera on a third person character. It works fine in UE4.9 but any newer versions add this weird almost brick-like border to it, how do i fix this and remove it >?

This is covered in Unreal Tournament Forum Downtime

Have updated my engine from 4.18.3 to 4.19.2 and got something like described above…
How can I fix it and why is it happening?

Okey, have noticed its a Chameleon FX problem

Likely a missing texture or compilation error within whatever Post Process material is currently active. Go to your Post Process effects and check the material for errors.