Make sure that you are logged in to access the event. When it is time for the event to start, the “Enter” button will no longer be greyed out. Click the “Enter” button on the event’s page to take you into the event.
If you login but still do not see the enter button on the event page, make sure you are using the account you purchased the ticket with.
You will have received a confirmation email when purchasing a ticket, and you can also confirm your purchase by accessing your “Purchase History” from the user menu in the upper-right corner of the screen.