edit:
This question was about a free service that no longer exists for viewing Sentinel 2 data from AWS before the 'requester pays' condition was put in place.
If you want to find out more on how to access data yourself consider the answer to this question or go to Sentinel Hub forum by Sinergise (the company that ESA pays to manage this data)
https://forum.sentinel-hub.com/c/aws-sentinel
specifically this thread