You get an infinite number of attempts! Any chance you've got an 8 that looks like a 3, or a 6 that looks like an 8, or a 5 that looks like an 8? You might be able to call the E-file help desk to see if they have any suggestions.

The e-file reject tells you which 1099-R is the problematic one. What's the payor name on that 1099R?