October 20, 2021
- Final deadline to resubmit a rejected return that was originally e-filed on or before October 15.
If mailing, it must be postmarked by that date. Some people who are rejected in that window say they include a copy of the rejection notice, but that's anecdotal. In any case, I'd at least save a copy of the rejection notice in case it's ever needed.
Also, if mailing, I would mail by a method that has tracking, such as certified return receipt or Priority Mail. Those services also document proof and date/time of mailing.
But we're hoping your efile return gets accepted so that you don't have to worry about it and undergo those extra steps. Good luck.
