There may be several reasons as to why your email address is not recognized:
1) Make sure you are registered to the event you are attending.
2) Make sure that the email address you entered is the one you used to register to the event.
3) If you entered your email address correctly, you might have made a mistake while registering to the event. Feel free to contact our support team through the following link so that we can check it for you.
Note that an email address can only be used for one person. If several people have been registered with the same email address, you will need to contact the organizer of your event to change it.