How can I fix the Transmission Error: Duplicate SSN error

If the IRS is saying another tax return has already been efiled using your SSN, there are at least two possibilities.

1. Someone fraudulently or mistakenly filed a return using your SSN.

2. You used the non filer portal to register for a stimulus payment and a return was efiled for you with $0 income in order for you to be registered. That portal was only to be used by persons not filing a tax return.

In either case, you will have to print and mail a tax return to get it accepted. The proper way to do it is for you to prepare, print and mail an amended return for 1040X that has the correct data for your return. Some have suggested that all you need to do is prepare the "real" 1040 and write "Amended Return" across the top of the form before mailing it. 

If you received this error, check all Social Security numbers in your return against their Social Security cards. You can do this by selecting the Personal Info tab and going through these screens again.

• If you come across any inaccurate entries, correct them and then try e-filing again.

If all Social Security numbers are correct, you will have to print and mail your return.  Another return has been filed using your Social Security number.

If you filed using the non filer portal on TurboTax or the IRS to register for the stimulus payment a tax return was e-filed with 0 income.

So the IRS already has a tax return with your SSN. 

That portal was for use by non filers only.

IRS Tax filing: Duplicate SSN issue/problem. We just faced this problem, few hours ago and panicked. We tried submitting a few times, and kept getting the same message, that
already someone else had filed a tax return, using the same SSN. However, we tried transmitting again after a half an hour, and to
our luck, it transmitted successfully with no errors. So, we think that this could be a software glitch or transmission glitch from
Turbo tax. I highly recommend you keep trying to submit, even if you get an error message, initially. Good luck!

So, I did my taxes early for the 2021 tax year - the IRS is not accepting returns until next week, yet I get the Duplicate SSN error message as if someone else has already filed taxes for the 2021 tax year under my social security number when I try to efile.  If the IRS was accepted taxes yet, I'd be worried about fraud.  But as the IRS isn't accepting them yet (that TurboTax is just holding them to file next week), I'm wondering if this is a TurboTax error.