Problems with LDAP

I am having trouble with LDAP. Now I use this code:

DirectoryEntry ldapConnection = new DirectoryEntry("LDAPS://*******.com:636", "User@bloom.local", "Password");

ldapConnection.AuthenticationType = AuthenticationTypes.SecureSocketsLayer;

DirectorySearcher search = new DirectorySearcher(ldapConnection);

var result = search.Filter = "(objectClass=*)";
search.FindAll();

I spent a large number of experiments, but never received:

Unknown error (0x80005000)

or

The server is not operational.

My property in the softerra LDAP Administrator:

The problem is that the simple authentication mechanism requires an LDAP distinguished name (DN) and you provided just a user name. At least, this is what your screenshot shows.

The DN of the administrator is likely something like cn=Administrator,cn=Users,dc=bloom,dc=local.

Also, I would probably steer away from using the administrator credentials in production. It is much more preferable to create an account with the right privileges.