LDAP authentication not working

[Maik Heinelt <ma...@servgate.co.jp.INVALID>]

I am not getting LDAP authentication with my Windows 2019 server to work. 
My guacamole.properties looks as following: 

guacd-hostname: localhost 
guacd-port: 4822 
GUACAMOLE_HOME: /etc/guacamole 

auth-provider: net.sourceforge.guacamole.net.auth.ldap.LDAPAuthenticationProvider 

# LDAP properties 
ldap-hostname: MyWin2019Server 
ldap-port: 389 
ldap-encryption-method: none 
ldap-username-attribute: sAMAccountName 
ldap-user-base-dn: OU=Users,DC=mydomain,DC=local 
ldap-search-bind-dn: CN=Administrator,CN=Users,DC=mydomain,DC=local 
ldap-search-bind-password: GoodPassword 


I got the ldap-search-bind-dn from the server LDAP admin properties >> Attribute Editor >> distinguishedName , so I am pretty sure this should be correct. 
I am able to reach the LDAP without errors with using SSL or also no encryption via Guacamole server command line using ldapsearch. 
When looking at the catalina.out log file, there is no error or warning shown when I try to authenticate via LDAP. 
Just a "WARN o.a.g.r.auth.AuthenticationService - Authentication attempt from [ callto:153.156.182.53 | 153.156.182.53 ] for user "MyUser" failed." 

Please correct me if I am wrong, but my understanding is, I should be able to authenticate with every user with its account name who is at the Users OU. 

Maik