Did you enter any income? You have to at least enter $1 of fake interest to let you efile. It won't affect your return.
Then You can try to switch to efile. Click on Add a State to let you back into your retun.
https://ttlc.intuit.com/community/e-file/help/how-do-i-change-from-mail-to-e-file-in-turbotax-online...
