First of all, check your gateway log (under C:\Program Files\Inductive Automation\FactoryPMI\logs\FPMIService.log.html) too see if the profile is able to connect to the LDAP server or not.
Second, assuming no problems with the connection, export an LDIFDE export of your active directory tree. To do this, open up a command prompt on a windows server machine and do a :
LDIFDE –f ADdump.ldf –s ABCDwhere ABCD is your domain controller. This will create a dump file called ADdump.ldf that contains your active directory tree in text format. (don’t worry - it doesn’t have sensitive info like passwords in it). This is very helpful in getting your LDAP queries correct (they are very unforgiving). You can email this dump file to us at support@inductiveautomation.com and we can help you more.
Hope this helps,