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How does Letterhead address unsafe links?

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Why does Letterhead check content links?

Section titled “Why does Letterhead check content links?”

Every email you send passes through filters that scan for spam, phishing, and other threats. If a filter is triggered, delivery can be interrupted or the message routed to spam — and persistent issues can get a sender marked “unreliable,” hurting IP addresses and domain reputations. Even trustworthy domains can be hijacked by malicious actors. To prevent security incidents and protect your email reputation, Letterhead verifies the integrity of the links in your content.

Why does my link redirect to the unsafe-link policy landing page?

Section titled “Why does my link redirect to the unsafe-link policy landing page?”

The link’s domain has likely been flagged as unsafe or unreliable on one or more Domain Name System blocklists (DNSBLs) — usually due to spam, phishing, or exploit-related activity. You can look up the domain on SpamHaus or Barracuda for details.

Section titled “How can I get a link delisted?”

If you own the domain:

  1. Check your domain on SpamHaus or another DNSBL platform.
  2. Identify the issue — common reasons include sending spammy email, running an open relay, being part of a botnet, or other activity seen as malicious.
  3. Address the issue — for example, secure a server that’s sending spam and close open relays.
  4. Clean your system — run thorough scans to ensure your servers are free of malware.
  5. Request delisting — use SpamHaus’s Blocklist Removal Center (or the equivalent for the blocklist involved), following their instructions and detailing the fixes you made.
  6. Monitor and follow up — reviews take time; if denied, address the additional concerns they raise.

If it’s not your domain: your options are limited. We strongly recommend swapping the links in your newsletter for safe alternatives — unsafe links can redirect readers to spam, block your delivery, or unknowingly serve malicious content, which can even carry legal consequences.

How do I appeal to Letterhead?

Section titled “How do I appeal to Letterhead?”

Once your delisting request has been approved by the blocklist, email [email protected] with the subject “Unsafe-link Appeal”, including the domain name and the link itself. We’ll re-check on our end, and if everything looks good, your links will be resolved. Note that this doesn’t prevent the domain from being blocklisted again — keep it secure.

For proactive tips on staying out of spam, see What can I do to improve my email deliverability?

Still can’t find what you need? Contact support.