Why does Outlook move emails from the inbox to the spam folder after arrival?

Email marketer from Mailjet mentions that low engagement rates (e.g., low open rates, click-through rates) can negatively impact sender reputation and lead to Outlook filtering emails as spam. Consistent engagement is important for maintaining a good sender reputation.

Email marketer from answers.microsoft.com responds that sometimes, Outlook's junk email filter might incorrectly classify legitimate emails as spam and move them to the Junk Email folder. Users can adjust the sensitivity of the junk email filter or add the sender to their Safe Senders list.

Marketer from Email Geeks explains that it’s called “time travel” where the email was originally sent to the inbox, but due to the spam complaint rate it is later moved to the bulk folder.

Email marketer from Tech Support Forum writes that If you've granted permissions to third-party apps, they might be sending mail on your behalf, and if these apps aren't reputable or are sending spam-like content, Outlook may filter these emails.

Email marketer from Reddit notes that Outlook's algorithm might be learning and adapting to user behavior. If a user frequently deletes or ignores emails from a particular sender, Outlook might start automatically filtering those emails to the Junk Email folder.

Email marketer from EmailOctopus shares that using spam trigger words, excessive punctuation, or all caps in the subject line or body of the email can trigger Outlook's spam filters and cause the email to be moved to the Junk Email folder.

Marketer from Email Geeks suspects that it's basically the SmartFilter being overworked and reviewing email with a delay, giving no other explanation.

Email marketer from Sendinblue indicates if your sending IP address has been used to send spam in the past, or if it's a new IP without a established reputation, Outlook is more likely to filter your emails as spam.

Email marketer from Reddit explains that if the sender's domain or IP address has a poor reputation, Outlook might automatically classify emails as spam. This can happen if the sender is on a blocklist or has a history of sending unsolicited emails.

Email marketer from answers.microsoft.com explains that incorrect rules or filters set up in Outlook can automatically move emails to the Junk Email folder. Users should review their rules and filters to ensure they are not inadvertently moving legitimate emails to junk.

Expert from Email Geeks says that it’s called “time machine” but thinks Kent is right, it’s “time travel.”

Expert from Spam Resource details that a poor sender reputation, often due to being listed on blocklists, directly impacts deliverability to Outlook. Outlook relies on sender reputation to filter out spam, so being on a blocklist can lead to emails being automatically directed to the junk folder.

Expert from Word to the Wise notes that if recipients mark emails as junk, it generates complaint feedback. High complaint rates can negatively impact a sender's reputation and lead to future emails being filtered as spam by Outlook.

Expert from Spam Resource says that Outlook considers user engagement as a critical factor. Low open rates, low click-through rates, and high delete-without-reading rates can signal to Outlook that the emails are unwanted, resulting in them being moved to the junk folder.

Expert from Word to the Wise shares that Microsoft's filtering can sometimes be overzealous and may move emails to the junk folder even if they appear legitimate. This can be due to various factors, including reputation, content, and user engagement.

Documentation from Microsoft Support details how adding an email address to your Blocked Senders List will send that email straight to your junk mail folder.

Documentation from Microsoft Support explains that adding email addresses and domain names to your Safe Senders List tells Outlook that these senders are safe. Outlook won't move messages from these senders to your Junk Email folder.

Documentation from Microsoft indicates that Outlook may move emails to junk if they fail email authentication checks like SPF, DKIM, and DMARC. These authentication methods help verify the sender's identity and prevent spoofing.

Documentation from Microsoft highlights that the SmartScreen Filter is a cloud-based anti-phishing and anti-malware technology. It evaluates emails and other content for suspicious characteristics and can move messages to the Junk Email folder if it detects potential threats.

Documentation from Microsoft says that individual user settings in Outlook, such as customized junk email filter settings or specific rules, can override general organizational policies and cause emails to be moved to the Junk Email folder. Users can adjust their own settings to control how email is filtered.