A user in ESS can receive this error for the following reasons:
They have entered the Verification code incorrectly. Users can copy the code from the email and paste it into the Verification Code.
The Verification Code is valid for seven minutes, after which time it will expire, and they will need a new code. Users can request a new code by clicking on Send new code. Delays in receiving the email could be due to the email being blocked or quarantined by the receiving mail server as spam, and it not reaching the user in time. If this is the case and you are using a work email address, you may need to reach out to your IT.