An administrator is not able to access the Admin console, as they are not able to proceed with the 2-step verification.
For direct Google account:
- Please access Google Toolbox recovery form.
- It will request to create a record to verify the domain's ownership
- An email with a confirmation will be received, follow the instructions on the email to recover the access.
For reseller account:
- Please contact the reseller as they can access to the Admin console to grant access to it.
Not able to validate the 2-step verification when accessing to the admin's account.