Bind your QQ / 163 / Gmail / Outlook / business mailbox to Laifaxin for unified multi-account send and receive — IMAP receiving + SMTP sending; usable in Compose / Mass Email / Smart Follow-up. Supports the vast majority of mailboxes (POP3 not supported).
Complete configuration flow for 263 Enterprise Mail — a long-established Chinese provider with many overseas nodes, friendly to foreign trade. You must first manually enable the Client Authorization Code feature in the web interface's Account Security section, then create a new code. When binding, fill in the authorization code, not the login password.
Complete configuration flow for Zoho Mail — note the Free plan does not support IMAP/SMTP; binding a third-party client requires a paid plan. Setup spans 2 sites: enable IMAP Access in Zoho Mail, and generate a 16-digit app-specific password in the Zoho Account Center. When binding, fill in the app password, not the main password.