Log in to Online TurboTax if not already logged in. Near the bottom of the left column menu go into Intuit Account. Then go to Sign In and Security. See if your email address is correct there (or you can change it to a different one), and if so see if it is "verified." If not verified there, see if you can verify it there with the adjacent link there. It may then send you a link to that email address to verify with. Once verified for the Intuit Account purposes, close Online TurboTax. And then sign in again.
That might be enough to fix it during efiling. When you try to efile, if it still wants to send you a 6-digit email verification code, be sure the code is not ending up in your email's spam/junk folder. See this FAQ on some tips, which also includes info on how you can change the email address in your Account Settings, if you wish to use another email address.
FAQ: What if I'm having trouble with my filing verification code?
https://ttlc.intuit.com/community/security/help/what-if-i-m-having-trouble-with-my-filing-verificati...
If that's not helpful, and the issue persists, please phone Customer Support.
Support hours are 5AM-5PM Pacific Mon-Fri this time of year.
FAQ: What is the TurboTax phone number?
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632
If you're using Free Edition and can't reach phone support, you can try reaching a support agent through Facebook or Twitter/X if you use social media:
Direct message a Support agent:
https://x.com/TeamTurboTax
or
https://www.facebook.com/turbotax
