Troubleshoot SendGrid in EonMailer

401 / 403 on connect

• Regenerate restricted key with Mail Send scope.
• Confirm key created on correct subuser if client uses subusers.
• Key revoked in SendGrid — create replacement.

Domain not authenticating

• CNAME points wrong host — SendGrid shows expected vs actual.
• Multiple conflicting SPF TXT — merge to one record.
• DNS propagation — wait up to 48h; lower TTL during setup.

Sends drop with “Unauthenticated”

• From address domain must match authenticated domain or single sender (production should use domain auth only).

Webhook events missing

• Event webhook disabled or wrong URL after deploy.
• SendGrid retry logs show 4xx — fix SSL/endpoint.
• Only some events enabled — add bounce + spam report.

Stats mismatch

• EonMailer counts provider events; compare SendGrid activity feed by msg_id.
• Clock skew rare; check timezone on scheduled sends.

Account suspension

SendGrid email with abuse notice — pause sends, audit list source, reply with remediation plan before resuming.