bobwhitacre wrote
$conf['plugin']['authad']['account_suffix'] = '@blah.edu';
$conf['plugin']['authad']['base_dn'] = 'DC=al.blah.edu,DC=edu';
If your domain is al.blah.edu the suffix should be @al.blah.edu.
The base_dn is configured incorrectly. This should be DC=blah,DC=edu (or DC=al,DC=blah,DC=edu if your domain is al.blah.edu).