Exactly. The error to aws s3api get-object --if-none-match ... is Could not connect to the endpoint URL: "https://foo.s3.eu-central-1.amazonaws.com/dir1/

Exactly. The error to aws s3api get-object --if-none-match ... is Could not connect to the endpoint URL: "https://foo.s3.eu-central-1.amazonaws.com/dir1/dir2/bar.json" At the "same" time SNS works.