SASL errors

In my slapd.log I'm finding a ton of the following error: SASL [conn=] Failure: no user in database\n In looking for this online, I mostly see it associated with bad ssh login attempts, but these errors don't coincide with ssh attempts on the server (our ODmaster) nor our fileservers bound to it. Is it possible that this can be generated via Apple Mail's auto complete feature when bound and using the Master for contacts?