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.

https://web.archive.org/web/20230611224026/https://old.reddit.com/r/help/comments/135tly1/helpdid_reddit_just_destroy_mobile_browser_access/jim40zg/

      • Much more efficient that Elon Musk. Done with much less attention. Most people even who are not “online” know Musk is doing bad stuff at twitter but is literally anyone aside from nerds paying attention to this? For those who are, will they remember in 1 month any details?

        People will maybe remember that a website whos’ members were known for being white supremacists and rapists got mad at some change being made.

        If this is some sort of gentleman’s game about who can most thoroughly dissect a major social media company, spez is in the lead.