Havin the same Problem.
As I wrote in the other thread I got to the point, that
UserAuthenticationBackend::register(new ClientLDAPAuthentication($config));
is called.
So from the class ClientLDAPAuthentication the function function __construct($config) is called, too.
But from the same class the function function authenticate($username, $password=false, $errors=array()) is never calles when a client tries to login. That seems to be my problem.
Unfortunately I'm a little bit lost in the file include/class.auth.php ...

KevinTheJedi I hope, it's OK to reopen this thread here.
I have the same problem: agents can log in via LDAP, clients can't.

Here are the specs of server:

LDAP plugin version is 0.6.2p8

What I did so far is extracting the phar as you described above and set some error_log statements in the file authentication.php.
So I found out, that the function authenticate in the class ClientLDAPAuthentication is never called. So the client login fails.

Any Ideas?

Cheers Bjoern