Besides it own internal user database, Syncplify.me Server! can authenticate users against the Windows user database and/or the Active Directory.
This article explains how to authenticate users against the Active Directory. A different article explains how to use the Windows (local) user database.
In order to authenticate an Active Directory user profile in Syncplify.me Server! you have to create a Syncplify.me Server!’s user that has the same username and domain name as your existing Active Directory user profile, as shown in the picture here below.
Select “allow password authentication” and choose “authenticate using Windows / AD” from the drop-down list indicated by the purple arrow here above. The user profile will be authenticated against the AD because it is written in the form “user@domain“. You may also use the alternative form “\\domain\user” shown below.
The key concept is that whenever a domain name is specified, the user will be authenticated against the Active Directory, and not against the local Windows user database.
In order to use AD authentication, the full username (including the domain name) must also be used on the client side; below is a screenshot that shows how to properly configure this in FileZilla, but the concept is valid for any other FTP/SFTP client.