Microsoft has resolved an issue that caused a spam rule to flag all outgoing emails as junk for some users of its Exchange Online Protection (EOP) service.
EOP is a cloud-based email filtering service that protects Exchange Online users from spam, malware, phishing, and other email threats. It also provides outbound email scanning to prevent users from sending malicious or unwanted messages.
On October 17, 2023, Microsoft acknowledged that some EOP customers were experiencing problems with a spam rule that incorrectly marked all sent emails as junk. The issue affected both Outlook and Outlook on the web users who had the junk email filter enabled.
According to Microsoft, the faulty spam rule was deployed as part of a regular update to improve the accuracy and effectiveness of EOP. However, the rule had a bug that caused it to misclassify legitimate emails as spam.
Microsoft said that it disabled the spam rule within hours of detecting the issue and restored normal email functionality for affected users. The company also apologized for the inconvenience and assured customers that it was taking steps to prevent similar incidents in the future.
How to prevent your emails from being marked as junk
While Microsoft has fixed the issue with the faulty spam rule, there are some general best practices that you can follow to reduce the chances of your emails being marked as junk by EOP or other email filtering services. Some of these best practices are:
- Use clear and concise subject lines that accurately describe the content of your email.
- Avoid using excessive punctuation, capitalization, or words that might trigger spam filters, such as “free”, “guaranteed”, “urgent”, or “click here”.
- Include a signature with your name and contact information at the end of your email.
- Use a reputable email service provider and domain name that have a good reputation and are not associated with spam or phishing activities.
- Verify your email address with Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-based Message Authentication, Reporting, and Conformance (DMARC) protocols. These protocols help authenticate your identity as the sender and prevent spoofing or impersonation.
- Keep your email list updated and remove any invalid or inactive addresses. Also, respect the preferences of your recipients and provide them with an easy way to unsubscribe from your emails if they wish to do so.
- Test your emails before sending them to make sure they look good and function properly on different devices and platforms. You can use tools like Email on Acid or Litmus to preview and test your emails.