This happened to me too, the rejection code was:
Reject Code Duplicate1099R
I had two identical amounts from the same payer to different payees. My guess is that the check is broken and they aren't checking payees in their duplicate detection, and that it is on the IRS side according to TT. The rejection only showed up a day or so after I filed. I'm adding a penny like others to see if it will go through.
