Why are my Cafe World waiters not serving?

My buzz rating is going down and the weird thing is, it started at 105.0 today and now it’s going down (It’s at 80 now). I didn’t change anything in the layout. My waiters (who are trapped) aren’t serving some tables even though there’s space. Another weird thing is they would serve this table and then later, they won’t. This won’t just happen to one table but a bunch of them. Help please? Thank you.