A user may not see the Sign Up button beside an event if: You have chosen NO as the Allow Users to Self-Register setting. (You can fix this on the Edit page for the event.) The cutoff date defined in the Self-Registration Cutoff field has been met for the event. All slots for the event are taken and the event is full. All slots for the event are reserved for a group to which the user does not belong. The Overflow option is not enabled for the Unaffiliated Users group (you can fix this on the event by editing the User Group Reservation).