Marketing emails not sending due to unexpected SMTP configuration errors

mohitanalyst
Wed, 18 Jun 2025 09:23:00 +0000

We’ve been struggling with email delivery failures for the past 48 hours. After updating our DKIM records for domain authentication on our primary sending domain, our marketing campaigns have completely stopped sending. The HubSpot email health dashboard shows “SMTP configuration error” but doesn’t provide specific details.

When I check the email domain settings, the DKIM status shows as “pending verification” even though our DNS team confirmed the TXT records were added correctly over 24 hours ago. We’ve tried re-verifying multiple times with no success.

Error from the sending logs:

SMTP Error: 550 5.7.1 Authentication failed
DKIM signature validation: FAILED
Domain: marketing.ourcompany.com

Our sales team is blocked from sending sequences and we have three major campaigns scheduled for tomorrow. Has anyone dealt with DKIM propagation issues in HubSpot? We’re on HS-2021 and this worked fine before the DNS update.