Greetings, IvaanPanda.
I see that you're trying to create screen recordings on your iPad Pro of a game that you play in order to upload those videos to YouTube. The issue is, you get an error, and I'm happy to help.
How to check the storage on your iPhone, iPad, and iPod touch -- Make sure you have sufficient space on your iPad Pro.
Restart your iPhone, iPad, or iPod touch -- If there is plenty of space on your iPad Pro, restart your iPad. Once it's returned to the Home screen, test the issue.
How to back up your iPhone, iPad, and iPod touch -- If restarting your iPad didn't resolve the issue, please be sure to have a fresh backup to keep your personal information safe.
If you can't update or restore your iPhone, iPad, or iPod touch -- Even though the title of the article isn't specific to your issue, the section titled "Put your device in recovery mode and set it up again" will walk you through all the steps to reinstall the iOS software on your device. Test the issue once again.
Let me know how that goes, and take care!