It crashing because you have downgraded your server version
because you downgraded from 1.14 it require you to reset your plugins and worlds

with is then much better to delete the server to create a new 1.12 server directly by using /create {name} 1.12

This happen because your world is 1.14 and you have downgraded the server to 1.12

You need to fully reset your world and reinstall all plugins to get it to work for 1.12
I recommend you to recreate the server delete it then create a 1.12 server directly with /create {name} 1.12

Every single command and chat is logged, each time you write a command or chatting were able to see it in bungee console @erik6147

Will never be secret even if we remove socialspy its still logged in logs 

The msg system is mostly to allow messaging across the whole network

Im going to check out today