See the detailed instructions here:
There are some common two-step verification problems that seem to happen more frequently than any of us would like. Here is how to fix this.
Step 1: Login using your Email and Password.
Step 2: On the next page, select Login Using Backup Code.
Step 3: Now, enter your Backup Code, which was given to you when you first created the account, and click on Login.
Note: If you do not have a Backup code, kindly create a support ticket.
Step 4: Once you hit on Login with the correct Backup Code, the below screen appears and your new Backup code will get generated. Please note it down for future reference.
Now hit on Continue.
You are now logged in to your account.