The search filter used to locate user DNs contains hard coded values that only work with Active Directory:
$mesg = $ldap->search( base => $search_base, filter => "(&(objectCategory=person)(objectClass=user)(sAMAccountName=$username))" );
This search filter should be configurable and should be in ldap.conf. Instead, it's hard coded in TrafficOps.pm.
For example, this search filter would work with most non-AD based LDAP severs: