1) If you are someone's dependent (like a college student), make sure you indicate that in the personal Info section, and that you did not supply more than half of your own support...then try again.
2) IF you are not someone's dependent, then you, or someone else has already filed a tax return with you and your SSN on it. Parent? ex? someone else's mistake? In this situation, you can only file on paper by mail and let the IRS sort it out. Change your filing method to file by mail. Print out your tax forms, sign, date, and mail them in......use a tracking method at the PO service counter so you get proof of delivery. If your state has an income tax, make sure you mail those in separately to the state's dept of taxation address. Yes....paper-mailed tax returns may take many months to get processed.