Client error: HTTP Status Code NOK

Response header:
HTTP/1.1 405 Method Not Allowed
Cache-Control: private
Content-Type: application/xml; charset=utf-8
Server: Microsoft-IIS/10.0
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Thu, 11 Dec 2025 11:22:19 GMT
Connection: close
Content-Length: 286
Response body:
<SubmitDataMultiResponse xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="SmsApi">
<ResponseStatus>
<ErrorCode>NotImplementedException</ErrorCode>
<Message>The operation 'SubmitDataMulti' does not exist for this service</Message>
</ResponseStatus>
</SubmitDataMultiResponse>