SMS API - PHP Error (Only SMPP endpoint allowed for this account)

Bonjour, je tente de mettre en place l'envoie d'SMS via l'API OVHCloud.

Je suis sur la fin, mais j'ai toujours cette erreur qui revient à chaque fois.
Que veut dire ce message d'erreur : **Only SMPP endpoint allowed for this account** ?

Génération du token : https://www.ovh.com/auth/api/createToken?GET=/sms/&GET=/sms/*&POST=/sms/*/jobs

Code :
$applicationKey = getenv("OVH_KEY");
$applicationSecret = getenv("OVH_SECRET");
$consumerKey = getenv("OVH_CONSUME_KEY");
$endpoint = 'ovh-eu';

$ovh = new Api($applicationKey, $applicationSecret, $endpoint, $consumerKey);

$result = $ovh->post('/sms/{SERVICE_ID}/jobs', array(
'charset' => 'UTF-8', // The sms coding (type: sms.CharsetEnum)
'class' => 'flash', // The sms class (type: sms.ClassEnum)
'coding' => NULL, // Deprecated: the coding is deduced from the message and its charset (type: sms.CodingEnum)
'differedPeriod' => NULL, // The time -in minute(s)- to wait before sending the message (type: long)
'message' => 'Test', // The sms message (type: string)
'noStopClause' => false, // Do not display STOP clause in the message, this requires that this is not an advertising message (type: boolean)
'priority' => NULL, // The priority of the message (type: sms.PriorityEnum)
'receivers' => array('+33000000000'), // The receivers list (type: string[])
'receiversDocumentUrl' => NULL, // The receivers document url link in csv format (type: string)
'receiversSlotId' => NULL, // The receivers document slot id (type: string)
'sender' => NULL, // The sender (type: string)
'senderForResponse' => false, // Set the flag to send a special sms which can be reply by the receiver (smsResponse). (type: boolean)
'tag' => NULL, // The identifier group tag (type: string)
'validityPeriod' => NULL, // The maximum time -in minute(s)- before the message is dropped (type: long)
));

print_r($result);