Diner has a slot open but guest won’t go

[PlanetMom]

I have 3 slots in my diner. Two guests are in there waiting to be served. A third guest has the diner option but it’s grayed out and says there isn’t enough room in the diner. Not sure what to do or how to solve the issue. Help

[QBIE]

Have u tried restarting the game? Other than that I don’t know. Sorry.