AutoSend API throwing '400 Domain verification required' even after adding DNS records — what causes silent verification drops?

Email Deliverability
1

We had domain verification configured and emails sending fine, but suddenly requests started failing with:
AutoSend API error 400: {"success":false,"error":{"message":"Domain verification required.","status":400}}

What causes verified domains to drop verification status, and what’s the fastest way to re-verify without interrupting production mail?

2

Why Domain Verification Fails After Setup

A 400 Domain verification required error means AutoSend’s background DNS checker detected that required authentication records (SPF, DKIM, or CNAME) are missing or non-matching during a periodic check. Common root causes include:

  1. DNS Provider Cache/Propagation Reset: Changes made at Registrar/Cloudflare level (like toggling proxy status on CNAME records or modifying TXT records) temporarily breaking TXT/CNAME lookup.
  2. Accidental Record Deletion: Removing DKIM k1._domainkey CNAME records during a DNS migration.
  3. Missing Custom Return-Path / MAIL FROM: Changing subdomains without updating DNS entries.

Step-by-Step Resolution

  1. Verify Live DNS Records via CLI:

    # Check TXT SPF
dig TXT +short yourdomain.com

# Check DKIM CNAME
dig CNAME +short autosend._domainkey.yourdomain.com

  2. Re-Add / Refresh Domain in AutoSend:

    • Go to Dashboard → Settings → Domains.
    • If records show red/unverified, click Check DNS Status.
    • If stale, remove the domain entry and re-add yourdomain.com.

  3. Required DNS Configuration:

    • SPF TXT: v=spf1 include:autosend.email ~all
    • DKIM CNAME: autosend._domainkey.yourdomain.com → dkim.autosend.com
    • DMARC TXT: v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com;

Note: DNS propagation usually takes 5–15 minutes. Once records return HTTP 200 / verified status in the dashboard, API calls resolve immediately without updating your API keys.

Relevant Documentation