Have you tried in incognito mode? If not, I suggest trying that or using a different device.

To change your email address:

1. Sign in to your TurboTax Online account.
   Do not click the Take me to my return button
2. Select Account Settings from the lower left corner.
3. This will take you to an Overview screen > Quick actions
4. Click Edit at the right of the E-mail address line.
5. Enter your new email address and confirm it.
6. Click Save, and you’re done.

Thank you for choosing TurboTax.