A problem with the dashboard, when u select a file to upload and you cancel it, it does not cancel the upload
/policy fails with 404 but the DELETE to /custom_domains/{domain} returns a 200 but does ~nothing~.eu it does really do something. Thanks!400 Bad Request or 404 Not found is definitely the better choice 
aws-sdk-js-v3 (https://developers.cloudflare.com/r2/examples/aws/aws-sdk-js-v3/#generate-presigned-urls){"ssl":"pending","ownership":"pending"} Is everything working ok now? access_key_id and access_key_secret. are they of aws ?

await getSignedUrl(S3, new PutObjectCommand({Bucket: 'my-bucket-name', Key: 'dog.png'}), { expiresIn: 3600 })let params = {
Bucket: bucket, /* Bucket name */
Key: fileName, /* File name */
PartNumber: partNumber, /* Part to create pre-signed url */
UploadId: uploadId /* UploadId from Endpoint 1 response */
};
const s3 = new AWS.S3(AWSData);
const res = await s3.getSignedUrl('uploadPart', params)