It says that I need to e-file taxes and send them back through the mail but I e filed online and signed

Was your return Rejected?  To check the status of your return, when you log into your TurboTax Online account, your filing status should be displayed on your homepage. You can also use our e-file status lookup tool to get your current status. 

If your return was rejected, check for an email from turbotax@intuit.com. It will give you a brief explanation of your reject and how to update it.  If you didn't get an email, open your return to get the rejection reason.

Sign in to your account and select the Fix my return button. Follow any “fix it” instructions to update the information causing the rejection.

Not all rejections will have explicit guides to fix the information. You’ll need to navigate to the program area to address the cause of the rejection, then proceed to the final step.

If what you originally entered is correct, you won't be able to e-file. There's probably a data mismatch at the government, a dependent that's already been claimed, or some other situation beyond your control that prevents your return from being e-filed. In these cases, go ahead and file a paper return, rather than wasting your time trying to "fix" something you can't fix.

To Re-File your return and if you were guided through fixing your reject, select the option to refile when you’ve finished.

If you had to navigate to the area in the program yourself, when you’ve finished, select File in the left-hand menu (mobile devices: go to the upper-left corner to open the side menu, then select File). Follow the onscreen instructions to either e-file your return or file by mail.

 If you get the same rejection a second time and you see no mistakes on your return, select the File by mail option to paper-file your return.