My smartermail 16 server is in the same domain, but when I enter the same LDAP string used by other .NET apps, it fails, complaining it cannot find the domain.

Any ideas?

Hi John. Have you enabled the domain's Active Directory Integration feature? Log in as the Administrator and edit the domain. Please ensure Active Directory Integration is enabled on the Features card. Then, manage the domain and from the Import from LDAP modal, input the location of your active directory users via the LDAP binding string. An example LDAP string might look like this: 

LDAP://testdomain.local/CN=Users,OU=Company,DC=testdomain,DC=local

If this doesn't work, I can help you contact the Support Department for their direct review. 

Connie, 

Yes, Active Directory Integration is limited to import and authentication only. It is a one-way connection. If your user is authenticated with AD, SmarterMail will always use their current AD password. In addition, the import will use only bring in their AD username (if directed to) and their AD password. All other account settings will default to what's set on the User Defaults template.