Found another workaround! Try: http://insecure.archiveofourown.org
A quote from the ao3 team (from reddit):
Older devices unable to load the site: Due to necessary updates in the site’s security, some older devices may be unable to access the site, getting a message like “could not establish a secure connection to the server”. If upgrading to a newer device is not an option, we maintain an insecure version of the site at http://insecure.archiveofourown.org which users on obsolete devices can access. Please be aware that using an insecure site can leave you vulnerable to having personal information such as password or browsing history intercepted.
Sign in doesn't work on the insecure site, however (and you shouldn't sign in, anyway, without HTTPS). For just reading and searching however, this may be a useful option.
I still think that it's a cloudflare SSL bug that should be fixed on their end, however. It doesn't appear to be the usual Cloudflare verification issue (which Raven mentioned), and seems like a problem with their Cloudflare configuration.
