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.
I had planned to leave reddit by end of June already, and have uninstalled Infinity from my phone a couple of days ago.
But man, this piece of news makes me wish I could do even more to boycott the platform. They are nuts. Enjoy the failure 😉