It’s not clear whether the issue arose due to a glitch or because the app had reached its Twitter token limit. Todd Thomas, a developer at Tapbots, said that the latter is not likely.
— Todd Thomas (@toddthomas) January 25, 2015
Nearly a day after the initial report, the app still hasn’t returned to the Mac App Store. 9to5Mac says that Tweetbot ‘seems to be switching back and forth between accepting a few logins and returning an error message.’
We’ve contacted Tapbots for more details and will update this post when we hear back.