I have found that my problem was the LDAP filter that probably was in the wrong format. I was passing the path to the OU where the users are , like this:
I removed the LDAP filter, Synced and all users (including some service accounts I wanted to filter) showed up in seconds!
What I should have, was a LDAP query to return users from a specific group, something like this:
Example 1: (memberOf=CN=QlikPowerUsers,CN=Users,DC=example,DC=com) returns all users and their attributes who are
members of the QlikPowerUsers group.
Example 2: (&(objectCategory=person)(objectClass=user)(cn=Joe*)) returns all users and their attributes whose name begins
mple,DC=com)) returns all users and their attributes who are members of either QlikPowerUsers OR QlikReadOnlyUsers groups.
More info about this on this very useful document:
Hope this also solved your problem!