Every event has a start and End date/Time and also every ticket sale has start and End date/time. If the ticket sale start date is of future date than the current date/time then the tickets will not show up. In order to make your tickets visible, please set the Ticket sale start date/Time to current date/Time.
Also check the status of your ticket whether it is in Published state or in Pause state. If out of many tickets, you want to have one or some of your ticket to be available for sale then just set the ticket sale Start date/Time to future date/Time, don't change the status to Pause. If a ticket is Paused, it will never be available for buyers.