enable system message replies
I’m not even sure in what case someone would reply to system 
?
Is the admin suppose to monitor the system PMs?
edit: discobot (and group messages apparently) are system messages, so that’s (at least partially) why
https://github.com/discourse/discourse/blob/master/plugins/discourse-narrative-bot/lib/discourse_narrative_bot/new_user_narrative.rb#L223