Social Security Questions? Ask a Social Security Expert
Have you remarried?
OK, did you sign for him? If so, did you put down any notation beyond his name signed?
What kind of return was it, i.e. 1040?
There can be a variety of reasons why it was rejected but the most popular relating to death of a spouse and filing jointly concerns a matching of the dates of death with the various entities. You will want to confirm that your return, and the death certificate have matching dates of death and that the SSA has properly recorded the date of death as well. The 3 must match.
I don't doubt that you properly recorded it, but working with the SSA as much as I do (daily), I see typos in their system with chronic regularity.
That would be my first check point.