When e-mail is received and filtered as spam, it is redirected to your Spam folder located in Web Mail. If you are using Outlook or a similar program, it will only download messages located in the Inbox.
You can have the spam filter, send everything to the Inbox, even if it is spam, so Outlook can download it.
Login to Webmail.
Click on Settings (located in the top right in 3.0)
Click on Anti-Spam
Click on Anti-Spam Settings
Enable the Spam to Inbox feature.
Click the button UPDATE SPAM SETTINGS.