AWS S3 Signature Does Not Match - amazon-s3

Question

I am stuck on s3.getSignedUrl and getting the error 'Signature Does Not Match, Signature calculated does not match...'. I have checked the credentials, and so many other things, but am not making any progress. I have my access key and secret saved in a credentials file.
The URL I'm getting back is https://postcard-photo-repo-dev.s3.amazonaws.com/Screenshot7.png?AWSAccessKeyId=AKIAJWHTSREEZUZGGO3A&Expires=1534619652&Signature=MkyVjARuo3PaO6lAYV6Li%2FAaR9E%3D
upload.js file:
function getSignedRequest(file) {
const xhr = new XMLHttpRequest();
xhr.open('GET', `/api/feed/sign-s3?file-name=${file.name}&file-type=${file.type}`);
xhr.onreadystatechange = () => {
if(xhr.readyState === 4){
if(xhr.status === 200){
const response = JSON.parse(xhr.responseText);
uploadFile(file, response.signedRequest, response.url);
} else {
alert('Could not get signed URL');
}
}
};
xhr.send();
}
function uploadFile(file, signedRequest, url){
const xhr = new XMLHttpRequest();
xhr.open('PUT', signedRequest);
xhr.onreadystatechange = () => {
if(xhr.readyState === 4) {
if(xhr.status === 200) {
$('#preview').src = url;
$('#avatar-url').value = url;
} else {
alert('Could not upload file');
}
}
};
xhr.send(file);
}
routes file:
router.get('/sign-s3', (req, res) => {
const s3 = new aws.S3();
const fileName = req.query['file-name'];
const fileType = req.query['file-type'];
const s3Params = {
Bucket: S3_BUCKET,
Key: fileName,
Expires: 600,
// ACL: 'public-read',
// ContentType: fileType
};
s3.getSignedUrl('putObject', s3Params, (err, data) => {
if(err) {
console.log(err);
return res.end();
}
console.log(data);
const returnData = {
signedRequest: data,
url: `https://${S3_BUCKET}.s3.amazonaws.com/${fileName}`
};
res.write(JSON.stringify(returnData));
res.end();
});
});