I am unable to load a new data screen. I am able to select data fields but then am unable to save the screen

I go through all the prescribed steps to load a new data screen, including selecting data fields and a preferred layout, but then can’t save this screen.  Selecting Done justr shows me the screen I have created, and pressing Return brings up a message asking if I want to “Exit without saving?”.   I am able to modify older screens, but can’t add a new one.   I only have 2 screens, so I don’t have too many.