I can't amend my return because it says my SSN does not match, but my SSN is correct.

When I first filed, I mistyped my SSN, I then corrected it and my return was accepted. Now I need to go back and amend my return, but it won't let me e-File because it says my SSN does not match the original form. I'm assuming it's checking against the first attempt which was rejected before I corrected the typo, but because of this I can't amend my return.