Why are emails suddenly going to spam in Outlook?

Email marketer from Email Marketing Forum shares that being blacklisted, a sudden spike in email volume, or poor list hygiene can cause emails to suddenly land in Outlook's spam folder. They recommend using a blacklist checker and segmenting email lists.

Email marketer from MarketingProfs explains that certain words, phrases, or excessive links in email content can trigger spam filters. They suggest reviewing email content for spam triggers and testing emails with a tool like Mail-Tester.

Email marketer from Email Sender Reputation shares that participating in feedback loops with Outlook can help identify and address spam complaints. This allows senders to remove subscribers who are marking emails as spam.

Email marketer from Reddit explains that sudden increases in spam filtering could be due to changes in Outlook's algorithms or new rules implemented. They also suggest checking sender reputation and ensuring proper authentication (SPF, DKIM, DMARC).

Email marketer from Email Marketing Tips explains that low user engagement (e.g., low open rates, high deletion rates) can negatively impact deliverability in Outlook. They suggest improving email content and segmenting email lists to target users with relevant content.

Email marketer from Email Deliverability Blog shares that a sudden drop in IP address reputation can lead to increased spam filtering in Outlook. They recommend monitoring IP reputation using tools like Sender Score and Postmaster Tools.

Marketer from Email Geeks shares that they received a message from Microsoft Support stating, "Thanks for your patience, we are currently experiencing technical difficulties and our engineers are working to resolve the issue at the earliest."

Email marketer from Stack Overflow explains that sudden increased spam filtering in Outlook could be because of a list bomb attack. A list bomb attack is where spammers subscribe an email address to a large number of services.

Marketer from Email Geeks shares that stating things plainly and leveraging what you see in SNDS for a given IP can improve Outlook ticket resolution. For example, stating "Sender manages list using filter (x), maintains low spam rates / trap hits are low," or dropping a screenshot from SNDS can get things handled more quickly, assuming the sender is performing well and abiding by best practices.

Marketer from Email Geeks confirms that sending information about what you're seeing in SNDS and the header scores helped finally get progress with Outlook tickets.

Expert from Word to the Wise explains that Microsoft makes frequent adjustments to its filtering logic, which can sometimes lead to unexpected changes in deliverability. These shifts can be triggered by various factors, including changes in user behavior or new spam tactics.

Expert from Word to the Wise highlights that senders should ensure their sending volumes are consistent with their reputation. A sudden, large increase in volume without an established reputation may trigger spam filters.

Expert from Spamresource shares that one of the first steps when troubleshooting sudden spam issues is to monitor if your sending IPs have been blocklisted by common blocklist providers. It recommends using a tool to check your IPs against multiple lists.

Documentation from DKIM explains that DomainKeys Identified Mail (DKIM) lets an organization take responsibility for a message by associating a domain name with it. This allows mail systems to verify that an incoming message from a domain was authorized by that domain's owner, and that the message has not been altered in transit.

Documentation from RFC explains that implementing SPF records prevents spammers from sending messages with forged 'From' addresses at your domain. When a mail server receives a message claiming to be from your domain, the server can query your DNS to determine if the source IP address is authorized to send messages from your domain.

Documentation from DMARC explains that DMARC (Domain-based Message Authentication, Reporting & Conformance) is an email validation system designed to protect email senders and recipients from spam, phishing, and spoofing. DMARC builds on the widely deployed SPF and DKIM mechanisms, adding a reporting function that allows senders and receivers to improve and monitor protection of the email channel.

Documentation from Google explains that their postmaster tools allows you to monitor deliverability.

Documentation from Microsoft Support explains that several factors affect spam filtering in Outlook, including sender reputation, email content, user complaints, and authentication. They recommend using the Junk Email Reporting add-in to report false positives and negatives.