Delete Faces

Hello. Can you upload some screenshots? Most likely you have some big faces that are not connected and you need to connect them with J to make a face so the shape holds up. Kinda hard to explain by text but with some visual reference it will be easier for us to figure out what is going on.

Oh, Rosy RRosy , I actually can't tell from the screenshots...

You probably made a mistake when Filling those Faces earlier...

If you can post a link to your .blend (upload it to Dropbox, GoogleDrive, or so), we might be able to pinpoint the exact thing(s) that go wrong.

Hey Rosy,

That's the .blend1 file, (that is sort of a backup) and that doesn't seem to be up to date with your problem version.

I had to Add a few Edges, but then those two Faces could both be Deleted without any problem:

Yep, that's the one, thank you!

So, the problem is actually the Bevel Modifier: disable Clamp Overlap and all is fine: