As quoted from the linked post.
It looks like you’re part of one of our experiments. The logged-in mobile web experience is currently unavailable for a portion of users. To access the site you can log on via desktop, the mobile apps, or wait for the experiment to conclude.
This is separate from the API issue. This will actually BLOCK you from even viewing reddit on your phone without using the official app.
Archive.org link in case the post is removed.
No I really mean it. That’s not a right that’s, like, in the Constitution, but it’s a principle of academic psychology and tech companies trample all over it. If it’s just, like, which button design is better or what CDN makes the page load faster, it’s mostly fine, but when they start asking questions like “what happens if we only show people the sad posts”, it’s really not fine.