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A message accepted by turboSMTP or a receiving server can still land in spam. Review authentication, recipient consent, list quality, and mailbox-provider responses. No provider can guarantee inbox placement.

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Check the delivery evidence

Find the message in Analytics and read its status and reason. Inspect the received message’s Authentication-Results header for SPF, DKIM, and DMARC outcomes. For bounces and complaints, review Suppressions and its Type column.

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Fix 1: Configure email authentication

  • SPF authorizes sending servers for the envelope sender domain.
  • DKIM signs message content and headers so receivers can verify the signing domain.
  • DMARC checks alignment with the visible From domain and publishes your failure-handling policy.
Use the exact DNS values provided for your domain in the dashboard. Merge SPF mechanisms into one existing SPF record. See Email Authentication, including subdomain setup and the dashboard verification step. The DNS analyzer can help inspect records. Confirm the result in DNS and received message headers; an analyzer result does not establish legal compliance or guarantee delivery.

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Fix 2: Clean your email list

Remove invalid addresses, duplicates, and recipients who have opted out or complained. Review inactive subscriptions before sending again. Use Email Validation as one check; validation cannot establish consent or guarantee that a mailbox will accept future messages.

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Fix 3: Provide an unsubscribe path

For subscription mail, provide a clear unsubscribe link and process opt-outs promptly. Configure turboSMTP’s unsubscribe element under Settings → Email elements → Unsubscribe link when appropriate for your messages. Keep application subscription preferences synchronized with Suppressions.

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Fix 4: Review tracking and content

Use accurate subjects, recognizable sender details, working links, and a useful text alternative to HTML. Avoid unexpected volume changes and send content recipients requested. If you use open and click tracking, review your tracking domain. A custom tracking domain uses a subdomain you control; it does not by itself guarantee better inbox placement. Availability depends on your plan: Free has a 30-day demo, Basic lists two custom tracking domains, and Pro lists unlimited domains. See pricing.

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Fix 5: Verify your sender domain

An unverified domain can use turboSMTP’s re-enveloped sender mode. The authenticated envelope or signing domain may then differ from your visible From domain, which can affect DMARC alignment or cause a mail client to show an additional sender label. Publish the dashboard’s SPF and DKIM records, complete verification, and check the domain authentication mode. Inspect a received message to confirm alignment. The appearance of an “on behalf of” label depends on the mail client and message headers.

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Fix 6: Investigate Yahoo and AOL complaints

Read the actual deferral or rejection reason in Analytics before assuming the cause. A complaint feedback loop provides visibility into complaints; enrollment does not remove a block or erase the effect of complaints on reputation. Yahoo’s current Complaint Feedback Loop uses Sender Hub and DKIM-domain enrollment. Its FAQ says older form registrations must be replaced by Sender Hub enrollment.
1

Check provider enrollment

Ask turboSMTP support whether your sending DKIM domain is already enrolled and how complaint processing is configured for your account.
2

Enroll if needed

Create a Yahoo Sender Hub profile, add and verify your DKIM signing domain, then enroll it in the Complaint Feedback Loop. Use a reporting address you control, or coordinate the reporting destination with turboSMTP support.
3

Act on complaints

Stop sending to recipients who complain. Review Suppressions for Spam entries and preserve opt-outs in your own application.
Yahoo guidance checked on 27 October 2026. For continued delivery problems, contact support with message IDs, timestamps, and redacted server responses.