Just want to update my situation in case it's helpful. After trying to see if I could talk to anyone at the IRS (unsuccessfully), I decided to try one more time to e-file. I used a different browser to log into TT (Chrome) and this time my return was accepted! I'm not sure why that is, as I've used Safari for the last 5 years and never had a return rejected, but I wanted to mention that in case that helps anyone else who's having the same problem. It may be just that the IRS or TT changed something in the back end of the software and it worked for me this time, I just don't know.
