Linux Users Are Unable To Manage Their Apple ID on Applecom (9to5mac.com)
For some reason, Apple's website where you can manage your Apple ID (appleid.apple.com) is blocking users of Linux browsers from accessing it. From a report: Having access to the website is important to manage things such as payment information, two-factor authentication, and other account details. Even though the number of Linux users accessing the website must be relatively small compared to other operating systems, some iPhone users who use Linux on the desktop noticed the issue. This behavior was first explained by user Alexander Martin on Mastodon. He discovered that when the browser reports itself as being a Linux browser, Apple's website will block the access by throwing a "Bad Gateway" error.
If the user-agent contains both Linux and Android, it's allowed.
Sounds more like some intern fucked up.
I just got in fine with Firefox on Fedora 29 and I'm not spoofing the user agent or anything.
It seems this was fixed within a few hours at most of the source article going up, and it's not clear exactly what user agent string got the error, or for how long, or even if that was definitely the thing that broke it. This is nothing.