The Tumblr's app has been deleted from both the App store and Google store, probably because the NSFW work on it breached their terms of use.

So, instead of taking care of the MANY pornbots that are already present on the site, staff, using their glorious glowing brain, decided to massban NSFW account, in a desperate attempt to get their app back on, apparently not realizing they are literally deleting the only thing that keep their wreck of a website from completely getting abandonned.