when sending mails to alfresco, alfresco matches the Email adress of the sender to an adress of an alfresco user. If no user ist found, than an error "nouser" is not in the group of email_contributors. The problem is, that matching is strict (case sensitive), which means that if the sender adress is Mike.Test@test.com it will not match against mike.test@test.com (which is the mail adress of an existing Alfresco user) and an error is thrown.
Is there a way to configure the matching process, i.e. that the mail adress is first transformed to lowercase? Or has this always to be case sensitive?