A user may not see the Sign Up button beside an event if:

  1. You have chosen NO as the Allow Self Registration setting. (You can fix this by going to Details and Editing the event.)
  2. The cutoff date defined in the Self-Registration Cut-off field has been met for the event.
  3. All slots for the event are taken and the event is full.
  4. All slots for the event are reserved for a group to which the user does not belong.
  5. The Reservation Overflow option is not enabled for the Unaffiliated Users group (you can fix this on the event by editing the User Group Reservation).