$ch = curl_init();

$data = array(
    "cc" => "COUNTRY_CODE",
    "phone_number" => "PHONE_NUMBER_WITHOUT_COUNTRY_CODE",
    "method" => "sms", // or "voice"
    "cert" => "VERIFIED_NAME_CERT_IN_BASE64",
    "pin" => "EXISTING_6_DIGIT_PIN" // required if two-step verification is enabled
);

curl_setopt($ch, CURLOPT_URL, "https://graph.facebook.com/v1/account");
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    'Content-Type: application/json'
));
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$response = curl_exec($ch);
if (curl_errno($ch)) {
    echo 'Error:' . curl_error($ch);
} else {
    echo $response;
}

curl_close($ch);

Exact same thing. Code above results in:

{"error":{"message":"Unknown path components: \/account","type":"OAuthException","code":2500,"fbtrace_id":"APrxxxxxxxxxxxxxlxux"}}