It means you either entered your Social Security number incorrectly or that someone has already used your SSN on a tax return. Make sure you entered the correct SSN in My Info. Correct if you entered it incorrectly, and try to e-file again. If you entered it correctly, then the only way you can file is to print, sign and mail your return. There is no way to e-file with a Social Security number problem.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.
Does your name on your social security card match the name you are using on the tax return? If you have changed your name it will show a mismatch and not allow you to efile.