With Two-Step Verification, even if someone obtains your MySonicWall username or email address and your password, they cannot access your account unless they also have access to your email account or your smart phone.
You may go to Settings | My Accounts page to change the Two FactorAuthentication method as per your preference

NOTE: With the email option, you have a few minutes to enter the code into the login screen. After a few minutes, you will need to start the login sequence over and use the code from the new email.
If the Code generated by the APP is not accepted, You may retry by doing the following:

If the above do not work, please contact the Customer Service by emailing customer_service@sonicwall.com. In your email please provide the following:
You can also contact Customer Service by phone and we will create a Customer Service case. You can find the phone number here: