Editing or Export Problems

Hello and I hope everyone is staying safe.

Im posting on here because I cant seem to solve a problem that keeps coming up. I film on an extra wide curved monitor. And when I edit the video it looks great. However, when I upload the video to Youtube it dosen't fill the screen. The video sits in the middle of the screen with black screen all around it. Any suggestions on how to fix this or wha the issue is?

Thank You