How do i confirm that email sender is a safe/legitimate contact

Question

How do i confirm that email sender is a safe/legitimate contact

ST 0

I have added an email address to my safe sender list however Outlook continues to flag every email with the message "We can't verify that this email came from the sender so it might not be safe to respond to it. Learn more." When I click "Learn More" it only takes me to instructions to report spam, phishing, etc but does not provide instructions to mark/verify/confirm contact is a "safe" so that I don't have to see this message on EVERY email to/from this contact. The email address is external to my organization but the contact person and email address are valid. The message is distracting and bothersome to see at the top of every email. Please help! Screenshot 2026-08-12 143947.png

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2 answers

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Answer 1

Adding the address to Safe Senders does not remove the Unverified warning in Outlook.

That warning is based on sender authentication checks, not on the Safe Senders list. Outlook shows it when the sender can’t be fully validated through email authentication methods such as SPF, DKIM, and DMARC. Safe Senders only affects junk filtering, such as helping keep messages out of the Junk Email folder.

What can be confirmed on the recipient side:

Verify the sender is on the Safe Senders list:
- In Outlook on the web, go to Settings > Mail > Junk email.
- Under Safe senders and domains, add the full email address or the sender’s domain.
- Select Save.
Check the sender indicators in Outlook:
- If Outlook shows a ? in the sender image, Outlook could not verify the sender identity.
- If Outlook shows a via tag, the actual sending address is different from what appears in the From address.
- In Outlook and new Outlook on the web, hovering over the sender name or address shows the email address without opening the message.
If the warning still appears, the fix is on the sender side:
- The external sender’s mail system needs correct and aligned SPF, DKIM, and DMARC configuration.
- Until those authentication checks pass consistently, Outlook can continue to show the warning even for a known contact.

Important caution: Using Safe Senders has security tradeoffs. Microsoft notes that this can increase the risk of malicious mail being delivered if a trusted sender is later compromised.

So the practical answer is:

Safe Senders = controls junk handling
Unverified warning = controls identity/authentication trust

There is no supported user setting in the provided guidance to manually mark that external sender as fully verified and suppress this warning.

Answer 2

Hi ST,

Thank you for sharing the details about your situation.

As this is a user-to-user community forum, I do not have the ability to directly access or modify your account or service. However, I can provide guidance, recommend next steps, share applicable resources, and direct you to the appropriate support channels so the issue can be investigated further.

I understand that you have already added the external email address to your Safe Senders list, but Outlook continues to display the warning stating that the sender cannot be verified.

The Safe Senders list helps prevent messages from being treated as junk or moved to the Junk Email folder. However, this warning is related to sender authentication and security checks, such as SPF, DKIM, DMARC, or anti-spoofing evaluation. Because of that, adding the sender to Safe Senders does not necessarily remove this verification banner.

Since this is controlled by your organization’s mail security and authentication policies, there is not a setting you can change as an end user to mark this sender as fully verified. Therefore, I recommend reaching out to your organization’s IT administrator so they can review the message headers, sender authentication results, and Microsoft Defender or anti-phishing settings. They may also need to coordinate with the external sender’s email administrator if the sender’s domain authentication records need to be updated.

For your IT admin references:

Additionally, if needed, your IT team can also raise a support ticket with Microsoft Support through the Microsoft 365 Admin Center for deeper investigation. They have access to backend configurations and can perform a more in-depth investigation. At the very least, they can provide the most effective workaround to ensure your experience remains smooth and secure.  

In case you do not know who is your IT admin, kindly refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support

I hope this helps move the case forward. Should you have any further questions or need additional assistance, please feel free to share them in the comment below. I'm very happy to help.

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