I had a weird situation with mine as I don’t need to file income taxes, so my last return was 2018 because of a sale of home (that did not get taxed). I wrote an executive summary explaining the paper trail. I gave them income documents from 5 years prior ( beginning and end of year statements) to show the history of non taxed money. They accepted it with no issue. The agent actually commended me on understanding my tax situation.
My friends was stuck in pending for 7 days. Took the advice of someone here (Tod, I think) and cancelled it and reapplied. The acceptance message came on day 3.