Missing Caterer and Musician from Wedding

One of my sims recently got married at a very nice venue I downloaded from the gallery. I set everything up, and the day of the wedding arrived, and none of the people I had hired showed up. There was no caterer and no musician. The mixologist is the only one who was there, but that was because the lot already had a bar and the game always spawned one when I entered the lot. I even tried hiring the caterer and the musician by clicking on their respective items and hiring them that way. I would get a pop up saying someone was on their way, but no one ever showed up.

Does anyone know what happened? I'd like to avoid this issue in the future.