I have a S3 bucket with Cloudfront in front of it (mainly so that I can use a nice custom domain name to access it whilst still having HTTPS support). It all works beautifully when accessing via a browser. But whenever I use any kind of HTTP client in code, the request never returns and times out.

I’ve tried iOS + Android HTTP clients, I’ve tried Postman, I’ve tried about five different Ruby on Rails HTTP clients – all of them behave the same way: it just sits there not responding and then times out. But if I request it through my browser, it responds almost instantly. Equally, if I change the URL and access the underlying S3 bucket directly, it works fine even from non-browser clients (this isn’t a long term solution since we’ve publicly shared the nice short URL in print etc).

Does anybody have any clue how to go about diagnosing this?

An example URL would be https://praynow4.org/care