I setup an Nginx proxy server to do SMTP/POP/IMAP authentication to upsteam mail servers. I have Smartermail and cPanel mail servers. I am able to get SMTP/POP working on both Smartermail and cPanel, however, I aways get "unable to log in at server, Probably wrong configuration, username and password" when testing IMAP for Smartermail. At soon as I switch upsteam mail server to cPanel inby garconcn - Nginx Mailing List - English