php - Facebook Marketing API. Pixel as Promoted Object. "Promoted Object Is Missing" -

i'm trying create adset using marketing api , using pixel promoted object such pixel. reason, error "promoted object missing". pixel connected ad account.

here code:

adsetfields::promoted_object => array(   'pixel_id' => $this->pixel,   'custom_event_type' => 'content_view',   'pixel_rule' => '{"event":{"eq":"pageview"}}', ), 

here json response:

"promoted_object" => array:3 [▼   "pixel_id" => "30xxxxxxxxxx63"   "custom_event_type" => "content_view"   "pixel_rule" => "{"event":{"eq":"pageview"}}" ] 

and here error messages:

"error_user_title" => "promoted object missing" "error_user_msg" => "your campaign must include ad set selected object promote related objective (ex: page, url, event). please update ad set continue."