Do I have to mail my return , it won’t let me e file

Can you tell me what the error code is, or what's on the screen not letting you e-file?

In TurboTax Online versions, these steps will change how you'll file your tax return(s) so that you can switch from file by mail to e-file: 

Note: These instructions apply to the current filing year only. (It's too late to e-file a 2016, 2015 or earlier tax return ). If you are trying to e-file any prior years return(s) they will need to be filed by mail. 

1. Open your return, if it's not already open, and select File from the menu on the left (if you don't see it, click or tap the 3 white lines in the upper-left corner to expand).
2. On the Just one more step screen, follow steps 1 and 2 if you haven't already.
3. Now select the Start button to the right of Step 3. This will take you to Here are your filing choices. Select I'd like to change filing methods.
4. Change your filing method to E-file and save your selection.
5. Continue following the onscreen instructions to e-file your return.
6. Finally, be sure to keep an eye on your email to track the status of your tax return.