Guest's Won't Stay Over

When I start a Stay-Over event in the calendar,  they never come over and the stay over event never actually begins.  I have tried multiple events with different guests and it never works. I have a bed for them and everything. 

Guests can initiate their own stay-overs, usually when my Sims have their first child, or sometimes we get random requests for it. But I cannot schedule a stay-over in the calendar.