Why is Google marking its own emails as dangerous?

Email marketer from Quora user EmailPro shares that another reason is that the content of the email might resemble phishing attempts or contain suspicious links. Google's filters are designed to detect these patterns, and even emails from legitimate sources can be flagged if they trigger these filters.

Email marketer from MailerCheck Blog explains that compromised accounts from trusted providers can still be seen as dangerous if the sender reputation of an IP used by the provider is low. Even though the email might pass SPF/DKIM authentication, the overall risk score of the sender can influence spam filters.

Email marketer from Reddit user u/EmailExpert shares that a possible reason is a compromised Google Workspace account. If a user's account is compromised, it can be used to send out phishing emails, and even though it is from a google.com address it will be marked as spam/dangerous.

Email marketer from GlockApps Blog shares that third-party apps with access to Gmail accounts can sometimes cause issues. If a third-party app is sending emails on behalf of the user and violates Google's policies, the emails may be flagged as dangerous.

Marketer from Email Geeks shares that it can still be an abuse channel, they may not have trusted something in the content of the message even though the source is Google itself.

Email marketer from Litmus discusses that emails marked as dangerous can be caused by an overall lack of proper email authentication (SPF, DKIM, DMARC). Poor sending practices can result in emails marked as dangerous, even if they are properly authenticated.

Email marketer from StackExchange user MailGuru responds that Google's algorithms constantly evolve, and what was once considered safe might now trigger security warnings. This can be due to changes in spam filtering techniques or the detection of new patterns associated with malicious activity, even from Google's own servers.

Email marketer from EmailToolTester Blog shares the sentiment that because a domain has DMARC it can still have delivery issues. They suggest that poor sending practices and mass mailing will result in Google marking its own emails as dangerous.

Email marketer from EmailGeekForum user NetOps shares that a potential reason Google flags its own emails is because of domain reputation issues. Even if the email originates from a Google domain, if the sending IP address or subdomain has a poor reputation, it can be flagged as dangerous.

Email marketer from SendGrid Blog states that poor quality content will result in Google and other ESPs marking emails as spam/dangerous. Even if an email is sent from Google, Google still actively reviews its content.

Expert from Email Geeks explains there are ways forgeries can get a DMARC pass and that it might be simple calendar spam and Google knows it.

Expert from Email Geeks explains it's because it’s not Google generated content, and there’s a lot of bad things being done via google calendar invitations.

Expert from Email Geeks shares she doesn’t think that’s a real google calendar invitation, and Google knows it. But you’d need to look at the full headers to know for sure.

Expert from Word to the Wise explains that a lot of mail identified as dangerous is the result of compromised accounts and/or infrastructure. If Google’s systems have been compromised this will result in Google flagging its own emails as dangerous.

Expert from Spam Resource explains that even Google's domains can be impacted by reputation issues if compromised accounts are used to send spam. A sudden surge in outbound emails can trigger filters, marking otherwise legitimate emails as dangerous.

Documentation from Google's Gmail Help Center explains that Gmail's spam filters are designed to identify phishing scams. These scams often spoof legitimate email addresses, including Google's own, and Gmail may mark these as dangerous to protect users.

Documentation from Google Postmaster Tools explains that Google uses various factors to assess the trustworthiness of emails, including authentication (SPF, DKIM, DMARC), spam complaints, and sending practices. Even if an email passes authentication, poor sending practices or high spam complaint rates can cause it to be flagged.

Documentation from Google Workspace Admin Help explains that Google may flag its own emails as dangerous if they originate from suspicious sources, even within the Google infrastructure. This could be due to compromised accounts sending spam or phishing attempts, or because the email content violates Google's policies.

Documentation from Google Security Blog explains that calendar invites can be abused to send spam and malicious links. Google has implemented measures to combat this, but some calendar invites may still slip through the filters and be flagged as dangerous due to their content or origin.