Why is my Render camera view cutting off with a square resolution?

With a Resolution of X: 500 px and Y: 500px in the Render -> Dimensions section the camera view seems to be cutting off. Notice how the red outline disappear at the top and bottom of the screen What am I doing wrong?

Uncheck “Lock Camera To View” for a moment and use the mouse wheel to scroll out a notch, then re-enable Lock Camera to View.

Pixelfox, that fixed it! I was very confused before. Thank you.