Google (Gmail) rejecting emails – SPF, DKIM & DMARC setup guide
Description
If emails sent from your domain to Gmail addresses are being rejected or marked as undeliverable, this is usually because Google has tightened its email authentication requirements.
Your domain must now have the correct SPF, DKIM, and DMARC records in place to verify that emails are sent from authorised servers.
You might see bounce messages such as:
- “550-5.7.26 This mail is unauthenticated, which poses a security risk…”
- “Message rejected. Please ensure all sending domains have SPF and DKIM set up.”
Cause
Google now requires all senders – including small businesses and transactional senders to meet its authentication standards.
If your domain is missing or has incorrect DNS records for SPF, DKIM, or DMARC, Gmail may reject your messages outright or deliver them to spam.
Solution
You can fix this by ensuring that your domain’s DNS has valid email authentication records.
In cPanel, open Email Deliverability to view or repair your DNS settings – this tool will automatically suggest the correct SPF and DKIM records for you to copy to your DNS host.
If your email is still being rejected after updating SPF and DKIM, we recommend also adding a basic DMARC record:
Name: _dmarc
Type: TXT
Value: v=DMARC1; p=none;Allow up to 4 hours for DNS propagation.