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You can get above error when you are creating an S3 bucket.
This error generally comes if you have deleted an S3 bucket in one region and immediately trying to create a bucket in other region with same bucket name.
Problem is that the S3 syncing is not instant across regions. It may take anything between 2 minutes to 30 minutes for the information to update in all S3 region that you have already deleted the bucket with that name.
You may get the same error even when you try creating same name bucket in different AWS account. Reason being same of syncing.
So if you want the bucket name to be same try creating it again after a coffee break.