I've seen other people mention this in their posts, but attention needs to be drawn to this. Why does the error even exist? Why does the game sometimes put you in a queue (very rarely) but most of the time just give you the error?

Shouldn't there always just be a queue? Or did the developers make a maximum queue size which is too small and this error comes up if the queue is full too?

I think the queue size needs to be able to handle a larger amount of people, so you can do something else while you're waiting to get in rather than just sit and spam a button.