Powershell LDAP query

I need to run an LDAP query on DC in another AD domain. I'm trying the following:
$cred = Get-Credential
$domain = [ADSI]"LDAP://DC01/ou=domain users,dc=company,dc=org"
$root = new-object system.directoryservices.directorysearcher $domain, $cred
$user = $root.findall()
$user
There's a heap of variations on the web and, for me they all return the same error:
Exception calling "FindAll" with "0" argument(s): "The server is not operational".
It may have to do with permissions; this script works fine on the local AD. Can't find out why the FindAll never works.
$cred = Get-Credential
$domain = [ADSI]"LDAP://DC01/ou=domain users,dc=company,dc=org"
$root = new-object system.directoryservices.directorysearcher $domain, $cred
$user = $root.findall()
$user
There's a heap of variations on the web and, for me they all return the same error:
Exception calling "FindAll" with "0" argument(s): "The server is not operational".
It may have to do with permissions; this script works fine on the local AD. Can't find out why the FindAll never works.