MyCloud EXT4 and Amazon S3

I have an Amazon S3 account with 3 buckets.
I have WD MyCloud EXT4.
I have configured MyCloud to backup on Amazon, but it always fail.
Is there any limitation on this kind of service?
I think the problem is about access key and private key. I’m using my email and password. Then I have used my account ID and my account name with the same password to connect.
When I’m using my e-mail and passowrd, it show sometimes a 0% status, and then a failure.
What can it be?

Hi litero,

You should refer this KBA in this concern.