Symptom: Sometimes a legitimate email message is falsely identified as spam.
Common Causes: Here are some of the most common causes for a legitimate email being filtered as spam:
- Filter levels are too aggressive: A message might have characteristics that make it look like spam, such as disclaimers, URLs, dollar signs, multiple exclamation points, or little or no body content apart from a link, image, or file attachment. The more such characteristics a message has, the more likely it will be quarantined, depending on the receiving user's filter levels. In particular, aggressive category filters can falsely identify valid messages as spam.
- Mail from a list server or news group: Since mailing lists and news groups send mail to many recipients at once, they often share characteristics with spam.
- An automated email service sent a spoofed message: Some servers, including group reservation and auction websites, sometimes send messages that appear spoofed and trigger spam filters.
- The sender's address was on a Blocked Senders list: Mail from a sender on your Blocked Senders list are quarantined as spam.
Solution: The appropriate solution depends on the problem's source. See below:
- If the mail comes from a sender who is often quarantined, including a web mail server, or a sender who has quarantined content, add the sender to your organization's Approved Senders list, or have the user add the sender to his or her individual Approved Senders list.
- For a mailing list where mail comes from many different senders to a single address, ask the user to add an Approved Mailing List. Note that the user should not add his or her own address to the Approved Mailing Lists.
- If your filters are too aggressive, consider asking your user to reduce filter settings, especially the Special Orders category setting.
- If the sender is on your Blocked Senders list for the user or organization, remove the sender from the appropriate list.
More Information: For more information, see Troubleshoot False Positives in the Administration Guide.