This is most likely
a browser issue.
Log out of TurboTax and Delete
any Intuit-related cookies and empty the browser's Internet cache. Then
close the browser, and reopen it. Try again, but on the sign-in page, be
sure there is no check mark for "remember me" until you get this
resolved.
If still no luck, then do the above steps again, and if your browser has
private browsing/incognito mode, try using a private window to access the TT
site.
If still having problems, you can try a different browser if you have one
available.