<?php
$code = "xxxxxx";
$client_id = "xxxxx";
$client_secret = "xxxxxxxx";

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, "https://api.dropbox.com/oauth2/token");
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, "grant_type=authorization_code&code=$code&client_id=$client_id&client_secret=$client_secret");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

$response = curl_exec($ch);

curl_close($ch);

$response = json_decode($response, true);

$refresh_token = $response['refresh_token'];

echo "Refresh Token: $refresh_token";

echo $response ;//*******  pridano  ********

?>

Notice: Undefined index: refresh_token in /home/users/xxxxxx/xxxxxxx/xxx/refrestoken.php on line 20
Refresh Token:
Notice: Array to string conversion in /home/users/xxxxx/xxxxxx/xxx/refrestoken.php on line 23
Array

takový výsledek je díky