After you file

my federal tax return was reject, quote ' the primary taxpayer's 

AGI or self select PIN from last year does not match IRS records'  I have used TT many times and not had this problem.  My husband died in July and I am filing jointly as his survivor.  The AGI number is correct from the 1919 tax return and the self select pin is one that TT generates.  TT tells me to print return and file by mail, I am reluctant to do this since electronic filing is much more convenient.  What prompts this rejection?, the death of a spouse or perhaps the vastly different income between 2019 and 2020?  In 1919 we had much higher income because of RMD withdrawal and higher pension income.  In 2020 I elected not to do an RMD so income was very low.