We could not e-file your return for the following reason:Duplicate Social Security Number: A tax return with the same Social Security number has already been submitted

Unless your SSN was entered incorrectly, that means a return has already been filed with your SSN. 

But since you are asking from TT Live, did your Live rep perhaps file it on your behalf?  If not, you will need to print, sign and file by mail.  And watch out for Identity Theft.

...AND

.......are you a dependent yourself? 

............Or do you have a child old enough to work, or is in college who may have filed a tax return?

Sometimes a dependent mis-files their own tax return, indicating they are not a dependent, when they actually are.   That will create a SSN e-file conflict between the Parent's and Child's tax file submissions, depending on who filed first.