IMAP and SMTP/POP (Dovecot + Postfix) configured wrong, don't know where to go next?

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http://unix.stackexchange.com – I have spent all day installing postfix, dovecot, postfixadmin, roundcube webmail and webmin. I thought that I had configured postfix/dovecot correctly, however upon logging into roundcube and trying to send a test mail, it just hangs there with the loading symbol on the browser. With that, I am left thinking that something is wrongly configured being it IMAP, SMTP, or POP. I am willing to provide a test mailbox to login if it is required/wanted. I have no idea which way to turn as I've already queried Google and real life friends. I would be highly appreciative if someone could offer me so (HowTos)