High School Prom not taking place

There have been several threads with this bug and all have the status "fixed", but I am still experiencing this bug. The Prom shows up in my calendar and I can invite others to prom but whenever it´s time for it, the prom just doesn´t start (on saturday 7pm). When I travel to the auditorium there´s no one there either.

I have tried all the solutions mentioned (like changing the lounges to houses etc.) but nothing worked.

I play on PC and without any mods.