This means your film gate is most likely different than your resolution gate.

An easy, albeit inaccurate, way to fix it fast with one click, is to turn on "Ignore res gate"

This usually happens when the resulution and/or focal length get changed when folks are trying out different lens-looks, and resolutions etc.

Happens to all of us
No big deal

Good luck!

PS: I moved this to the right forum as well