Nodejs - AWS SNS publish is called, but message is not being sent - node.js

Question

I'm trying to publish a SNS message to a single user.
The message is working when I manually press the "Publish Endpoint" button in the AWS console, but I'm trying to send it programmatically using the SNS nodejs SDK.
I have made sure to create a single IAM role giving full access permissions to SNS.
I have made sure to configure it:
const AWS = require("aws-sdk");
AWS.config.update({
region: process.env.AWS_REGION,
accessKeyId: process.env.AWS_ACCESS_KEY_ID,
secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY
});
I first create a platform endpoint using sns.createPlatformEndpoint(endPointParams) and it works fine so my IAM role is not an issue.
Using the result from that call, I use the data to create publishParams to make a call right after creating the endpoint:
let payload = {
user : "Hihih test",
shopping_list : "shopping_item"
};
let endPointParams = {
PlatformApplicationArn: process.env.REACT_APP_SNS_ARN,
Token: req.body.device_token
}
const createEndPoint = sns.createPlatformEndpoint(endPointParams).promise();
createEndPoint.then(data => {
console.log(data.EndpointArn);
console.log(JSON.stringify(payload));
let publishParams = {
Message: JSON.stringify(payload),
MessageStructure: 'json',
TargetArn: data.EndpointArn
};
sns.publish(publishParams, (err, result1) =>{
console.log("Success");
});
return;
}).then(result => {
res.status(200).send("Success sending invite to user.");
}).catch(err => {
console.log(err);
res.status(500).send("Something went wrong sending the invite.");
});
});
The console.log("Success"); inside sns.publish() is being fired, but on the client side, the app does not receive a message. I have also tried multiple times to manually call "Publish Message" in the console and it works fine.
So what could my issue be? I think it's something wrong with my code.

Answer 1

When using SNS with GCM you need to structure your JSON payload with the keys GCM and default or it will throw an err.
var payload = {
default: 'Hello World',
GCM: {
notification: {
title: 'Hello World',
body: 'Notification Body'
// other configs can be put here
}
}
};