With version 1.27.0 of MediaWiki and last snapshot of "LDAP Authentication" (from today 08/04/2016), I obtain a message "Auto-creation of a local account failed: Automatic account creation is not allowed." to the first connexion of users.
It seem cause by a change in default config : "MediaWiki will now auto-create users as necessary, removing the need for extensions to do so. An 'autocreateaccount' right is added to allow auto-creation when 'createaccount' is not granted to all users." (https://www.mediawiki.org/wiki/Release_notes/1.27)
Enable "autocreateaccount" is no needed.