If you currently try to access Twitter without logging in to your user account, you may find you’re unable to see any of the content that was previously available to the wider public. Instead, you’ll likely be met with the Twitter window that asks you to either sign in to the platform or create a new account, effectively blocking you from viewing tweets and user profiles or browsing through threads unless you’re a registered Twitter user.
Several members of The Verge team have been able to replicate the issue, and it appears to be affecting web access on both desktop and mobile devices. Prior to this change, Twitter allowed people limited access to the platform without an account — you could view public tweets and user profiles, for example, but couldn’t like or leave comments. A window that prevented readers from viewing additional posts until they signed in also previously appeared after the viewer had scrolled past an undisclosed number of tweets, though that at least allowed some access to the platform.
https://www.theverge.com/2023/6/30/23779764/twitter-blocks-unregistered-users-account-tweets