I’m having trouble with my email delivery setup and wondering if anyone has experienced something similar.
I’m using an external email service to handle transactional messages from my application. The sender address is configured as my company’s Gmail for Business account. Here’s what I’m seeing:
Messages to non-Gmail recipients work perfectly
When sending to Gmail addresses, nothing shows up in the inbox
The service dashboard shows successful delivery status
Already verified spam folders are empty
Has anyone run into Gmail potentially filtering messages that originate from Gmail accounts but route through third-party SMTP providers? I’m trying to figure out if this is a known limitation or if there’s a configuration issue on my end.
It sounds like you’re dealing with a common issue related to Gmail’s handling of DMARC policies. I’ve encountered a similar problem while using SendGrid where emails sent from our business Gmail account never reached Gmail inboxes, despite showing as delivered. Gmail’s strict authentication measures can sometimes result in such emails being dropped without notification. Transitioning to a dedicated sending domain with properly configured DNS records improved our deliverability significantly. I recommend checking your DMARC reports or considering a dedicated domain to see if that resolves the issue.
You’re sending transactional emails from your company’s Gmail for Business account via a third-party SMTP service. Emails to non-Gmail addresses are delivered successfully, but messages sent to Gmail addresses disappear without appearing in the inbox or spam folder, even though your service dashboard shows successful delivery. This is likely due to Gmail’s strict authentication and routing rules for emails originating from Gmail accounts but sent through external SMTP providers.
Understanding the “Why” (The Root Cause):
Gmail employs sophisticated mechanisms to prevent email spoofing and spam. When an email appears to come from a Gmail address (your company’s Gmail for Business account) but is actually routed through an external SMTP server, Gmail’s internal filters become highly suspicious. Perfect SPF and DKIM records—while essential for email authentication—aren’t enough to override this internal routing check. Gmail’s system flags these emails as potentially malicious, leading to silent rejection and non-delivery.
Step-by-Step Guide:
Switch to a Dedicated Sending Domain: This is the most reliable solution. Instead of using your [email protected] address as the sender, create a dedicated domain specifically for transactional emails (e.g., [email protected]). Configure this domain’s DNS records (SPF, DKIM, DMARC) properly to authenticate your emails. Set the Reply-To header in your emails to your existing Gmail address if you need responses to reach your inbox.
Verify DNS Records: Ensure your DNS records (SPF, DKIM, DMARC) for your new sending domain are correctly configured and propagated. Use online DNS checkers to confirm they are correctly set.
Test Email Delivery: Send test emails to various Gmail addresses and monitor your new domain’s email delivery using the tools provided by your external SMTP service.
Common Pitfalls & What to Check Next:
DNS Propagation Time: It might take some time (up to 48 hours) for DNS changes to fully propagate.
Firewall Issues: Check if your firewall is blocking outbound SMTP connections on the ports used by your service.
SMTP Service Configuration: Double-check the sender authentication settings within your third-party SMTP service provider’s control panel, ensuring the domain you’ve selected is correctly linked.
Gmail Postmaster Tools: If you are still facing delivery issues, consult Gmail’s Postmaster Tools to gain insights into the reasons behind non-delivery. It can provide feedback on email authentication and other factors impacting your emails.
Still running into issues? Share your (sanitized) config files, the exact command you ran, and any other relevant details. The community is here to help!
Hit this same problem six months back with automated invoice emails. Gmail’s routing logic was the culprit - it flags messages sent FROM Gmail addresses through external SMTP as potential spoofs, even with proper authentication. Fixed it by switching the sender to something like [email protected] instead of the Gmail business address. Just set the reply-to header to your Gmail so responses still reach you. Also check if your external service connects with Gmail postmaster tools - helped me figure out why messages were vanishing instead of hitting spam.
Understanding the “Why” (The Root Cause):
Step-by-Step Guide:
Common Pitfalls & What to Check Next:
Still running into issues? Share your (sanitized) config files, the exact command you ran, and any other relevant details. The community is here to help!