BSNL Dlt - "Unknown error attempting to reach phone" / "Phone carrier has blocked this message" - Promotional Messages, Registered SenderID, TemplateID, EntityID - Nodejs

So, after following through the aws docs I have completed the process of DLT Registration and have successfully received a Certificate (BSNL Dlt) with the EntityID.

Now in the DLT console I have created the SenderID and TemplateID as well (both were approved by the DLT) and am using the same to send an SMS to my users.

I raised a case with AWS also to register my SenderID and I do see the same has been approved and AWS Pinpoint SMS reflects this

Following is the Code that I am using :

async publishToPhone(phoneNumber, message) {

    var params = {
      PhoneNumber: phoneNumber,
      MessageStructure: 'string',
      Message: message,
      MessageAttributes: {
        "AWS.SNS.SMS.SenderID": {
            DataType: 'String', StringValue: 'TNPNWS'
        },
        "AWS.SNS.SMS.SMSType": {
            DataType: 'String', StringValue: 'Promotional'
        },
        "AWS.MM.SMS.EntityId": {
            DataType: 'String', StringValue: '1401599xxxxxx65494'
        },
        "AWS.MM.SMS.TemplateId": {
            DataType: 'String', StringValue: '1407170xxxxx49047'
        }
    }
    };
    
    const data = await sns.send(new PublishCommand(params));

    if (!data) {
      throw Error(`There was an error in publishing ${params.Message}`);
    }

    return data;
  }