Wavy Corners on sides

I just got the 4k UST projector and the corners are wavy. I’ve tried everything to fix it and I can’t. Any suggestions? Yes it’s on a smooth surface and the projector is level.


Did you solve this?
I have similar but different issue

This is caused by your screen not being perfectly flat. If its wrinkled/warped which could be common on a retractable screen it will not be straight. You can confirm this by pulling on the screen