Implementation:
$apiMail = AccountFactory::instance($host, $format);
$account = new AccountSelector(AccountBy::NAME(), $email1);
$apiMail->auth($account, $pass);//account as admin
$prefclass = new Pref("+zimbraPrefMailForwardingAddress", $email2);
$pref = $apiMail->modifyPrefs([$prefclass2]);
I don’t have any errors on running, but forwarding not working.
Any ideas ?