在facebook营销Api中搜索国家时没有国家/地区

i've tried to fetch the country that facebook provided for the marketing api in the adset.

in the past 2 days i'believe that i've got the country data. but today i am not get the data for the country

this is the code for doing that

        $result = TargetingSearch::search(TargetingSearchTypes::GEOLOCATION, null, $country, ['location_types' => ['country', 'region', 'country_group']]);

if i try use another location like region or city like i define above it returning the city and the region

is there anything wrong with my code? or is there any change between the api

i am using PHP SDK 2.8 thanks