I am not publishing s3 video, I am publishing bunnyCDN video. It takes bunnyCDN url and applies amazon signed URL to it. Please see the url in my earlier post and the first part of URL.
Here is the info requested.
( System Info removed )
I resolved it. Eventhough AWS was showing that my cloudfront distribution is enabled, looks like it was not. I waited for 3 hours and it automatically started working. :)