Try each of the following until the issue is resolved: 
  1. In the top filters, ensure that the date range includes the event's date. 
  2. Ensure that the event is not part of a multi-level event, which cannot be sold through Web forms. 
  3. Make sure that the program is set up to include registration
    1. Go to Events > Program Search
    2. Search for and open the program record
    3. On the program record, confirm that the text "Requires Registration" is showing
    4. If "Requires Registration" is not showing, go to Web > Manage Program forms and you should see your event there