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emails being sent to gmail addresses

Kevin Smith 0 Reputation points
2026-05-25T02:17:02.8+00:00

All emails being sent to gmail addresses are bouncing back, showing code errors of SPF or DKIM

Outlook | Web | Outlook.com | Email
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  1. EmilyS726 242.8K Reputation points Independent Advisor
    2026-05-25T02:50:46.6+00:00

    Hello

    What email domain do you use? Outlook.com/hotmail.com, or your custom domain?

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  2. AI answer

    2026-05-25T02:17:14.56+00:00

    All bounces with SPF or DKIM errors indicate that Gmail is rejecting the messages because email authentication for the sending domain is not correctly configured or not aligned.

    For Outlook.com or other Microsoft consumer accounts sending to Gmail, do the following on the sending domain (the domain that appears in the visible From address):

    1. Confirm the domain is properly authenticated
      1. Publish a valid SPF record in DNS for the domain that includes all systems/services used to send mail (for example Microsoft, any marketing platform, on‑premises servers). Use a public SPF checker to verify the record syntax and that it passes.
      2. Publish DKIM records (public keys) in DNS and ensure outbound mail is DKIM‑signed.
      3. Publish a DMARC record for the domain (for example: v=DMARC1; p=none) and ensure that either SPF or DKIM aligns with the domain in the From header.
    2. Check alignment and header results on a bounced message
      1. Open one of the bounced messages in Outlook and view the full internet headers.
      2. In the Authentication-Results header, verify:
        • SPF: pass and the SPF domain matches (aligns with) the From domain.
        • DKIM: pass and the d= domain matches (aligns with) the From domain.
        • DMARC: pass (DMARC uses SPF/DKIM plus alignment).
      3. If SPF or DKIM shows fail or none, or DMARC shows fail, fix the corresponding DNS record or signing configuration, then resend.
    3. If sending high volume If sending 5,000 or more messages to Microsoft consumer services (Outlook.com, Hotmail, Live, MSN) with the same From domain, all of the following must be in place for that domain:
      • SPF and DKIM records published and both checks passing.
      • DMARC record published.
      • Messages passing DMARC (SPF and/or DKIM aligned with the From domain). The same best practices apply when sending to Gmail; misconfigured SPF/DKIM/DMARC will cause rejections.
    4. Typical SPF/DKIM/DMARC failure causes
      • Missing SPF, DKIM, or DMARC records in DNS.
      • Incorrect SPF (wrong IPs or senders not included) so Gmail’s SPF check fails.
      • DKIM not enabled or not signing all outbound mail.
      • Misalignment: the SPF or DKIM domain does not match the From domain.
      • Forwarding or relaying through other systems that breaks SPF/DKIM.
    5. After fixing DNS and signing
      • Wait for DNS propagation (often up to a few hours).
      • Send a new test message to a Gmail address and re‑check the headers for SPF/DKIM/DMARC pass.

    If DMARC continues to fail, use the information in the NDR and headers to identify whether the problem is missing/incorrect DNS records, missing DKIM signing, or forwarding/relaying that breaks authentication, then correct those specific issues and retest.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

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