I recently came across this issue and it won't happen always but I came across it 3 times.
This happens when a player is banned and tries to join the server. It won't stop spamming the notification unless you disable BanManager and enable it or restart the server.

https://i.gyazo.com/0fce51ef31d923d5169145263bc1e75d.png

Here is an other example from the log file:
http://pastebin.com/3G3xfZ2t <= excuse my language in ban reason, I thought the user was using some kind of bot.

EDIT: Just updated the servers to latest development build but still having the same issue.

Thanks in advance!

Closed because this is an issue with Multi-Lobby redirection plugin.