php - 'Bad Request' when using 'wp_remote_post' in Wordpress

one text

<form method="post"> 
 <input type="text" name="telNum"/> <br />
 <input type="submit" value="continue" name="adslSubmit"/>

I have created the form above in index.php and want to make remote api call with wp_remote_post function but when i var_dump it i get bad request.

 if(isset($_POST["adslSubmit"])) {
   $sum=$_POST["telNum"];
    $body = [
   'phone'  => '02144365296',
 ];
$ApiUrl = "https://apis.mabnatelecom.com/api/inquiry";
$bodyRequest = array(
"headers"=>array(
'Content-Type' => 'application/json',
'Authorization' => 'Bearer 63428f4b7cb735b9d0d59f0bd539656f',
),

"body"=> $body,
);

 $api_response = wp_remote_post($ApiUrl,$bodyRequest);
echo 'before';
var_dump($api_response);
echo 'after';

}

The way i should send data to api is:

 {
  "phone" : "02144365296"
 }