Hai.
I have see many people ask a similar question like me and i have try every step over in the discussion but i'm still failed in automatically created a message in the user message wall.
I have created MediaWiki:Welcome-message-wall-user and MediaWiki:Welcome-message-wall-anon. After that i invite my friend to do some editing and created a new blank page. But still, the message is not appearing.
The fandom that i created can be found in [[1]]
I appreciate any suggestion and feedback you give in order to solved this problem of mine.
Thank you.