2 Players cannot connect at once?

So I've in counted this issue where 2 or more people cannot connect to my bungeecord server. I found this out when I restarted on of my servers and when we tried to connect to the hub it always gave us an error or kicked whilst connecting to hub. So in there a way so 2 or more people can connect at the same time?

Also I was wondering how other bungeecord servers do this. How do you make it so when a server restarts they are automatically pushed to the hub?