Configure Mailgun with FluentSMTP

Mailgun needs a verified sending domain and a private API key. The region in FluentSMTP must match the region of that domain (US or EU).

In Mailgun

1. Sign in at app.mailgun.com.
2. Add and verify a domain under Sending → Domains. Publish the DNS records Mailgun shows.
3. Open API security. Create a Mailgun API key (not the webhook signing key, not the verification public key). Copy it once.

EU domains live in the EU region. Everyone else is usually US. Wrong region looks like "domain not found" when you save.

In FluentSMTP

Settings → FluentSMTP, pick Mailgun, or Add Connection → Mailgun.

• From Email on the verified domain.
• Private API Key.
• Domain Name: the sending domain, for example mg.example.com or example.com, exactly as Mailgun lists it.
• Select Region: US or EU.

Leave Store in Database selected. You can tick Disable Encryption, or switch to Store in wp-config.php. Both are optional. See Where secrets are stored.

Save Connection Settings, then send a test.

The plugin's key link is app.mailgun.com/settings/api_security. Mailgun moves that UI occasionally. If the link 404s, open Account → API Security from the dashboard.