Domain Not Found Error When Using Django Anymail with Mailgun

Other Questions Mailgun
1

I’m having trouble setting up django-anymail with Mailgun for email delivery. When I try to send an email using Django’s email function like this:

send_mail('Hello World', 'This is a test message content', '[email protected]', ['[email protected]'])

I keep getting this error message:

AnymailRequestsAPIError: Sending a message to [email protected] from [email protected]
ESP API response 404:
{
  "message": "Domain not found: testdomain.com"
}

What’s causing this issue and how do I fix it?

Here’s my current configuration:

ANYMAIL = {
    "MAILGUN_API_KEY": "key-myapikey123",
}
EMAIL_BACKEND = "anymail.backends.mailgun.MailgunBackend"
DEFAULT_FROM_EMAIL = "[email protected]"
2

The 404 error indicates that Mailgun does not recognize testdomain.com within your account. It is essential to first add and verify your domain. Navigate to Sending > Domains in the Mailgun dashboard to add testdomain.com. Mailgun will provide the necessary DNS records to set up with your domain registrar, typically including MX and TXT records. Once the domain is verified, ensure your ANYMAIL settings have the correct MAILGUN_SENDER_DOMAIN. Mailgun restricts outgoing emails from unverified domains to avoid spam.

3

Had this exact problem six months ago switching from SendGrid to Mailgun. Everyone’s right about domain verification, but there’s another thing that got me. After adding your domain and updating DNS, check you’re using the right API endpoint. If you’re on EU servers, add “MAILGUN_API_URL”: “https://api.eu.mailgun.net/v3” to your ANYMAIL config. Also make sure your API key matches the domain you’re sending from - I used a key from the wrong Mailgun account and got the same 404 errors. Verification takes a few hours, so don’t freak out if it doesn’t work right after adding DNS records.

4

Domain verification’s just the beginning. Even after verifying testdomain.com in Mailgun, you’ll hit rate limits, deliverability problems, and SMTP config headaches.

I learned this the hard way managing email at scale. Django email becomes a nightmare when you need reliable delivery, bounce handling, and proper error management.

What saved me was switching to automation. Instead of fighting Django’s email backend, I built workflows that handle everything automatically.

The system monitors your app’s email triggers, routes them through multiple providers if needed, handles failures smoothly, and gives you actual visibility into what’s happening.

You can add retry logic, fallback providers, and A/B test email templates without touching Django code.

This saved me weeks of SMTP debugging and gave me way better delivery control.

Check out Latenode for these email automation workflows: https://latenode.com

5

check if u’re accidentally using the sandbox domain. mailgun’s sandbox only sends to authorized recipients - you need to switch to ur verified domain. make sure MAILGUN_SENDER_DOMAIN matches exactly what’s in your dashboard.

6

hey, you gotta add testdomain.com to your Mailgun account. check it in the dashboard first b4 sending any emails. look under ‘Verified Domains’ in the Mailgun console.