API Authentication Failed

[Web-H]

Hi, I tried to use WHMCS' API but something wrongs.

 

This is my code:

 

<?php

$url = "https://mywhmcs.com/whmcsfolder/includes/api.php";
$username = "api-username";
$password = "api-password";

$postfields["username"] = $username;
$postfields["password"] = md5($password);
$postfields["action"] = "addcredit";
$postfields["clientid"] = "116";
$postfields["description"] = "test";
$postfields["amount"] = "1.20";

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, 100);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $postfields);
$data = curl_exec($ch);
curl_close($ch);

$data = explode(";",$data);
foreach ($data AS $temp) {
  $temp = explode("=",$temp);
  $results[$temp[0]] = $temp[1];
}

if ($results["result"]=="success") {
  # Result was OK!
} else {
  # An error occured
  echo "The following error occured: ".$results["message"];
}

?>

 

But, when I'm going to the page, this error appears:

 

result=error;message=Authentication Failed;

 

 

IP address has been added on IP allowed list, and for the API account, the API access is checked.

 

How can I resolve this problem ? Thank you in advance

 

- - - Updated - - -

 

I tried too to go directly on https://mywhmcs.com/whmcsfolder/includes/api.php?username=api-username&password=md5-encoded-password page

but, on this page, I get "result=error;message=Authentication Failed;" error too.

 

(IP address allowed and API access checked on user group)