Troubleshooting email deliverability

If your Katalyz emails aren't reaching recipients consistently, here's the systematic approach.

The fastest fix: dedicated subdomain

If you haven't set up a dedicated email subdomain yet, that's by far the most impactful fix. See Setting up a dedicated email subdomain.

After subdomain is set up

If you're still seeing deliverability issues:

1. Verify DNS records are correct

Recheck SPF, DKIM, and DMARC. Tools that help:

• mxtoolbox.com — SPF and DKIM lookups
• dmarcian.com — DMARC report analysis
• mail-tester.com — send a test email, get a score

2. Check recipient-specific issues

Some buyer domains are stricter than others:

• Large corporations (Microsoft, Google, Oracle) — often have aggressive filtering
• Government domains — tighter still
• SMB on Gmail/Outlook — typically easier

For a specific buyer who isn't receiving, see I didn't receive the email.

3. Warm up a new subdomain gradually

If you just set up the subdomain, it has no sending reputation. Ramp up volume slowly — don't send to 10,000 contacts on day one. Send to 100, then 500, then 2,000 over the first week.

Katalyz automatically handles some of this, but heavy manual sends can trigger spam filters on new subdomains.

Content-side improvements

• Avoid aggressive marketing language (URGENT!!!, FREE!!, click here)
• Balance images and text — all-image emails are spam-flagged
• Don't use URL shorteners (bit.ly, tinyurl) — use full URLs
• Keep subject lines under 50 characters

For truly difficult cases

• Ask IT on the recipient side to allow-list your subdomain
• Use an alternative channel (Slack, Teams, phone) to pass the link manually when email fails

Related articles

• Setting up a dedicated email subdomain
• Email is landing in spam
• I didn't receive the email

Updated on: 18/06/2026