Just today Ryanair wouldnt let me in on Firefox. 403 with a cloudflare error.

But on chrome it went through without a hitch.

I’ve been using Firefox for 20 years, and Ryanair for 10, I’ve never had to switch browser for it. My last flight was 2 weeks ago

Its the magic of multi-metric based DDOS/exploit/whatever protection.

For my full profile the login attempt with Firefox as a user agent apparently pushed it over the edge.