Error
Connection lost could not connect to a default or fallback server please try again latter:io.netty.channel.abstractchannel$AnnotatedConnectionExpactaion

Solution
If Bungee
Your bungee server may be misconfigured. Check the sub-servers IP. If that does not work. Check the bungees config and make sure that the listeners IP running on your servers IP.

If Spigot
Your spigot server may not be functioning properly. Try to restart it.