S3 AMAZON error has been blocked by CORS policy

hello Guys,
I am trying to upload a photo on S3 Amazon by the course LiveView of the PragProg.
And I am having some errors.
on the application tells it complains for:
“External client failure”.

And on my console it complains for:

Access to XMLHttpRequest at 'https://<mybucket>.s3.amazonaws.com/' (redirected from 'http://<mybucket>.s3.amazonaws.com/') from origin 'http://www.localhost:4000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

and other error:

uploaders.js:21 POST https://<mybucket>.s3.amazonaws.com/ net::ERR_FAILED

In my configuration CORS I put:

        "AllowedHeaders": [
        "AllowedMethods": [
        "AllowedOrigins": [
        "ExposeHeaders": []

I am trying to change the configuration on permissions but it’s not working.
Can anyone help me with this, please?

I edited again the configuration CORS with the same values and now it is working.
Maybe it was needed some time for work.
I don’t now, but it’s working now.
I want now If someone knows a place(tutorial or book) for the case to use the S3 for production.
Like this things I don’t know like the List of the control access and ACLs?

I have the same errors. May I ask where you created and used the above headers?


on the course you can see on the Chapter: 34. File Uploads - Notes.
It has the links: