If you, as a publisher, are contacted by a new user indicating that they've encountered a confirmation token is invalid error, follow the procedure below:
Navigate to the Users module by clicking the Users link in the Sales dropdown menu.
Find the user record in question.
Verify that the user is confirmed.
If the user is not confirmed, click the Confirm User link at the top of the page. Note: The link won't be visible if the user is already confirmed.
NOTE: If the user was confirmed, they should have no problem logging into the site. They simply clicked the Confirm my account link twice. Note: The confirmation email describes this potential error at the bottom of the message.
