The plate needs to be a solid without opening in middle. The feature you have created is a "frame" and this is the reason your "grill" can't be created.
HTH
Please mark "Accept as Solution" and "Like" if my reply resolves the issue and it will help when others need helps.
= ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ = ♪ = ♫ =
A circle is the locus of a cursor, starting and ending at the same point on a plane in model space or in layout such that its distance from a given coordinates (X,Y) is always constant.
X² + Y² = C²
![Autodesk Design & Make Report](https://forums.autodesk.com/t5/image/serverpage/image-id/1350519iCB55845EBFC43016/image-size/large?v=v2&px=999" "Autodesk Design & Make Report")