Captchas depended on websockets which were removed.
https://github.com/LemmyNet/lemmy/issues/3200#issuecomment-1600505757
“Note that captcha uuids and answers were stored in-memory in the websocket server which is removed now, so its necessary to add a new database table for captchas.”
Hehe, lemmy.world doing some stress testing for the entire lemmy project.