https://techcrunch.com/2023/01/16/twitters-third-party-client-issue-is-seemingly-a-deliberate-suspension/

Last Friday, a ton of popular Twitter clients including Tweetbot, Twitterrific, and Echofon were down. Users couldn’t log into their accounts or look at their timelines. At first, it looked like a bug in Twitter API, but radio silence from Twitter and new details indicated that the company deliberately limited access to third-party apps.

On Friday, late evening PST time, many users noticed that they could not access their third-party Twitter clients. The app makers quickly acknowledged the issue and said that they had been trying to contact the company.