The guest login code was something I wasn't a fan of and so I deleted it. For now you can get guest functionality by creating an account and deleting it quickly to dodge backups. It's not a good solution but it does let you try the site without being locked in. I also don't require e-mails and the site is completely free so hopefully creating a login isn't too big of an ask. (I definitely get if it is and I may bring back the guest logins if it makes sense.)