SharePro is ownCloud app which adds autocomplete feature to email field in share dropdown dialog.
Email search is performed against LDAP database which is used by LDAP user and group backend.
This app requires user_ldap and appframework to be installed and enabled.
SharePro uses LDAP connection and configuration from user_ldap app. If several LDAP servers are configured then only the first one will be used.
Make sure you have set User Search Attributes and User Display Name Field on Advanced tab of LDAP user and group backend configuration page.