Cannot cut object with another by using boolean or knife project

Support Basics & Interface
1

It seems that I cannot cut a hole into my object either by using the boolean modifier or the knife project as seen in the below video:

The knife project generates an error and has something to do with the circle line but not sure what it means.

Can anyone tell me what I’m doing wrong or how I can get around this issue?

2

I think you’re attempting to do a knife projection incorrectly. Perhaps this video tutorial in this other thread will help better clarify what setup is required.