Sometimes Gmail incorrectly marks messages coming from senders outside your domain as spam. As an administrator, try the steps in this article to fix the problem, and prevent it from happening in the future.
Troubleshooting tips
Actions all users should take
Encourage people in your organization to:
Mark incorrectly classified messages as Not spam
Gmail uses machine learning to better understand your preferences, and to recognize spam. When you manually mark a message as not spam , Gmail learns how to manage messages addressed to you.
Add trusted senders to your personal contacts list
Users in your domain can manage their personal contacts list in Gmail. When a user adds an external address to their contacts list, Gmail won't mark messages from the external address as spam.
Action for admins to take
Add trusted senders to the spam bypass filter
Create an allowlist by adding domains or addresses to a list of senders that bypass Gmail spam filters. Messages from domains or email addresses in your spam filter are more likely to be delivered to users' inboxes.
Note: If Gmail identifies a message as potentially suspicious, it can be rejected or sent to spam, even if the sender is in your allowlist.
Action external senders can take
Tell your trusted customers, suppliers, and others to authenticate their sent email. Google recommends using these email authentication standards.
Best practices for email authentication
We recommend you always set up these email authentication methods for your domain:
- SPF lets servers verify that messages appearing to come from a particular domain are sent from servers authorized by the domain owner.
- DKIM adds a digital signature to every message. This lets receiving servers verify that messages aren't forged, and weren't changed during transit.
- DMARC enforces SPF and DKIM authentication, and lets admins get reports about message authentication and delivery.
Follow Gmail bulk sender guidelines
To optimize delivery of large volumes of email from Gmail or third-party senders, read Prevent mail to Gmail users from being blocked or sent to spam .
