Response: StatusCode: 404, ReasonPhrase: 'Not Found'

I was trying to read a fax and the following error was thrown "Response: StatusCode: 404, ReasonPhrase: 'Not Found', Version: 1.1, Content: System.Net.Http.StreamContent, Headers: { Connection: keep-alive RCRequestId: a02bf940-ea3d-11e9-9b97-005056afc229 RoutingKey: SJC01P13PAS07 X-Rate-Limit-Group: medi "

FaxResponse response = null;

try
{
    using (RestClient rc = new RestClient(RINGCENTRAL_CLIENTID
                                        , RINGCENTRAL_CLIENTSECRET
                                        , IS_PRODUCTION))
    {
        TokenInfo token = await rc.Authorize(RINGCENTRAL_USERNAME
                                            , RINGCENTRAL_EXTENSION
                                            , RINGCENTRAL_PASSWORD);
        if (rc.token.access_token.Length > 0)
        {
            CreateFaxMessageRequest request = new CreateFaxMessageRequest
            {
                attachments = uploadedFiles.ToArray(),

                faxResolution = "High",

                to = new MessageStoreCallerInfoRequest[]
                {
                    new MessageStoreCallerInfoRequest { phoneNumber = toPhoneNumber }
                }
            };

            response = await rc.Restapi().Account().Extension().Fax().Post(request);

            return response;
        }
    }
}
catch (Exception ex)
{
    ins_error_log log = new ins_error_log();
    log.runSP(ex, false);
}

return response;