Disable Spam filter at SmarterMail.
As smartermail has it’s own antispam feature, it will place the e-mail that suspect to be spam into it’s own spam folder. As a result, customer that using standard e-mail client like OUTLOOK, Or Thunderbird will not be able to retrieve the e-mail.
This is affecting customer that using IP ServerOne smartermail hosting; and using POP3 to retrieve the e-mail. POP3 protocol can only pick up the e-mail from INBOX.
To disable the antispam feature, Login into the webmail http://webmail.xxxx.com/ and follow the instruction at the screen shot below: