Comment 2 for bug 1561657

I don’t travel that much, but the few occasions I tested it in the past it worked as intended (last time was several months ago though, the platform has evolved a lot since then, and it’s not impossible that this particular functionality has regressed).

In my experience, captive portals will redirect you to their login page if you browse to a plain HTTP URL. Browsing to an HTTPS URL won’t do the redirection. And usually pages like e.g. google.com get you HTTPS by default. So you might want to try a page for which you’re sure there won’t be encryption (try e.g. http://example.org), just in case that’s where the issue lies.

Marking incomplete for now, more information to help the understand the issue better is welcome.