Sina Mail (@sina.com / @sina.cn): Enable IMAP/SMTP + Generate 16-char Client Auth Code
Complete setup for Sina personal email (@sina.com / @sina.cn / @2008.sina.com) — turn on IMAP/SMTP service via web [Settings → Client POP/IMAP/SMTP], pass SMS verification to generate a 16-char client auth code, and paste it into the Laifaxin password field (not the login password).