I need to amend my return, but every time I try, it says “this isn’t available right now” and to check back at a later date. Originally it was 2/15, now it is 2/22.

I just need to add a 1098E form I forgot about. I realized immediately after I filed (of course) that I forgot a form that will make a large difference to my return. How long do I need to wait to make this addendum?