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.
