I rarely use my phone for Medium but I know a lot of people do. It's hard to understand why they would cut off such a large group of writers/readers - I can usually make up a story to explain these things but all I can come up with here is that they haven't been paying their software development bills and it's coming back to bite.

I've not been on Medium long - about a year - but the only thing I've found that can be relied on is that inexpicable things will happen regularly - sometimes they'll turn out to be glitches that are repaired, other times they'll turn out to be new features. The way to tell a feature from a glitch is that features don't get repaired.

On the plus side, it's giving you more time to write your books. Good luck with them