Difficulty in mplementing webhook

[Kaushal_Didwani]

I am trying to send a whatsapp message through REST API to client once a new row is added so i am using webhook. I am implementing the following things in AppSheet:

Preset: Custom
Url: https://app.messageautosender.com/api/v1/message/create
HTTP Verb: Post
HTTP Content Type: JSON
Body:
{
‘username’ : “user”,
‘password’ : “Psw”,
‘recipientIds’ : “<>”,
‘Message’ : “Hi”
}

But this is not working… I am getting a bad response error…

However in App Script the following code is working,… Can anyone tell me what changes needs to be done in Appscript…

var params = {
‘username’ : Username,
‘password’ : Password,
‘receiverMobileNo’ : MobileNo,
‘Message’ : Message
};

var options ={
‘method’ : ‘post’,
‘payload’ : params
};

var result= UrlFetchApp.fetch(“https://app.messageautosender.com/api/v1/message/create”, options);

Have been trying to figure out my mistake from months but unable to do so. Please help if possible.