MAGENTO 2.1.9 API for Custome Attributes doesnt get the values- URGENT

Hello, Our developer is having a lot of trouble and we are in need of an expert high level developer with a lot of experience. The error is : that the Magento API is not getting the values from custom_attributes when we try to add a product with the API : .'/[login to view URL]' HERE IS THE CODE EXAMPLE: /// attributes // $custom_attributes = array( array( 'attribute_code' => 'category_ids', 'value' => [ $category_id ] ), array( 'attribute_code' => 'description', 'value' => $product['product_description'] ), array( 'attribute_code' => 'short_description', 'value' => $product['product_name'] ), array( 'attribute_code' => 'manufacturer', 'value' => $manufacturer_id ), array( 'attribute_code' => 'upc_code', 'value' => $product['product_code'] ), ); $requestUrl= $data['store_url'] .'/[login to view URL]'; $add = [ "product" => [ "sku" => $product['product_sku'], "name" => $product['product_name'], "price" => $product['retail_price'] , "status" => $product['status_magento'] , "visibility" => 4, "type_id" => "simple", "attribute_set_id" => 4, "weight" => 1, "custom_attributes" => $custom_attributes, "extension_attributes" => array( "stockItem"=> array("qty"=> $product['quantity'], "isInStock" => true) ), ] ]; $headers = array("accept: application/json","content-type: application/json","authorization: Bearer ".$data['token']) ; $ch = curl_init(); $ch = curl_init($requestUrl); curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST"); curl_setopt($ch, CURLOPT_HTTPHEADER, $headers ); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($add) ); $result = curl_exec($ch); $result = json_decode($result); $result = (array) $result ; Here is the error we are receiving: Error occured during "custom_attributes" processing. A custom attribute is specified withou an attribute code. If you have experience with this and know how to help us - I will gladly pay you well for your time.