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.
You can spoof the user-agent, it’s a PITA but not that hard. I did it to use chat gpt with bing, but didn’t bother for Reddit
I recommend libreddit, no commenting and it’s slower, but at least it works on mobile
Unfamiliar with the way libreddit retrieves its data. If it’s supposed to work after API BS, I’m guessing good ol’ scraping?
It uses the API. They’re discussing what to do next, probably “wait and see” for now https://github.com/libreddit/libreddit/issues/785