too long

I am new in LDAP and I have issue with binding. Here is my code:

$con = ldap_connect(11.11.11.11); // LDAP server is placed at another machine
ldap_set_option($con, LDAP_OPT_PROTOCOL_VERSION, 3);
ldap_bind($con, "cn=Michael,cn=Users,DC=example,DC=com", "password");

Looks like everything is fine with connection. The error appears on ldap_bind:

ldap_bind(): Unable to bind to server: Internal (implementation specific) error

I have tried to google this error but found nothing. When I change DN to incorrect on purpose another error apears that says "bad credentials". It means everything is fine with DN and password. Please, help.

The cn of "Users" (cn=Users) is likely to be your organizational unit (ou). Have you tried the DN: "cn=Michael,ou=Users,DC=example,DC=com" ?