Creating AdSet via FB Marketing API - php

Question

I'm trying to create AdSet via FB Marketng API, but getting Error 100 (Invalid parameter). I'm even try to paste sample code from FB Developers Docs, but it is the same Error. Please help.
This is my code:
use FacebookAds\Object\Targeting;
use FacebookAds\Object\Fields\TargetingFields;
$targeting = new Targeting();
$targeting->{TargetingFields::GEO_LOCATIONS} =
array(
'countries' => array('US')
);
/**
* Step 4 Create the AdSet
*/
use FacebookAds\Object\AdSet;
use FacebookAds\Object\Fields\AdSetFields;
use FacebookAds\Object\Values\AdSetBillingEventValues;
use FacebookAds\Object\Values\AdSetOptimizationGoalValues;
try{
$start_time = (new \DateTime("+1 week"))->format(DateTime::ISO8601);
$end_time = (new \DateTime("+2 week"))->format(DateTime::ISO8601);
$adset = new AdSet(null, $account_id);
$adset->setData(array(
AdSetFields::NAME => 'Adslondon1',
AdSetFields::CAMPAIGN_ID => '6070381098103',
AdSetFields::LIFETIME_BUDGET => '50',
AdSetFields::TARGETING => $targeting,
AdSetFields::OPTIMIZATION_GOAL => AdSetOptimizationGoalValues::LINK_CLICKS,
AdSetFields::BILLING_EVENT => AdSetBillingEventValues::LINK_CLICKS,
AdSetFields::BID_AMOUNT => '10',
AdSetFields::START_TIME => $start_time,
AdSetFields::END_TIME => $end_time
));
$adset->create(array(
AdSet::STATUS_PARAM_NAME => AdSet::STATUS_PAUSED,
));
echo 'AdSet ID: '. $adset->id . "\n";
}