Can't create a custom sized document

I have to make very specific sized ads for work using Indesign.

I have been doing this for months and have never had a problem creating custom sizes.

All of a sudden today, I tried to create a new document for one of the ads I'm making and it will not let me make it the size that I need to make it.

When I enter the W & H in pixels it automatically snaps back to it's own number.

I even tried going to document setup after opening a new document from one of the presets. I then went to "custom" and

It gave me an error message saying "this page does not fit with the current margin and column settings. select the appropriate pages in the pages panel and then adjust using the margins and columns dialog box"

I read through the ID forum and tried what was suggested. I reset my preferences, uninstalled and re-installed the program. Nothing is working.

I really need this to be fixed.

Thanks