For those trying to e-file, it is my personal experience with 2021 taxes that after 5 (FIVE) failed attempts in a row, you're done. The IRS computer will not accept it after the fifth failed attempt even if all the information is correct. You have no choice but to print, sign, and mail the return to the IRS.
Had this happen with a relative whom I was assisting, and the rejection message received from the IRS computer was something along the lines of (can't recall exact wording) "TO MANY ATTEMPTS. MAXIMUM REJECTS/FAILURES EXCEEDED" or something along those lines. The rejection e-mail further indicated the return would have to be mailed.
