Mailgun has thresholds in place that if exceeded will result in a domain being temporarily disabled. These limits are in place to protect your email reputation in case your system is compromised by a spammer or someone in your organization makes a large mistake.
If you do not have a good reputation tied to your domain and IP address, your email will not reach your recipients’ inboxes.
The number one reason we see people get blocked is because they have a bad mailing list. Most of these lists have bad email addresses and include spam traps. ESPs are good at recognizing bad mailing lists.
Best practices for lowering bounce rates include:
- If you think your application has been compromised, change your SMTP credentials or API key through the Mailgun control panel.
- Clean your mailing list of invalid email addresses.
- Only send emails to recipients that have signed up to receive them.
- Verify the email address is correct with a confirmation email (aka, confirmed opt-in).
- We recommend using our free email validator at the point of signup to reduce invalid email addresses.
- Don’t purchase your list or scrape websites for emails.
If your domain does get disabled, contact support after you have made the recommended changes above so we can re-enable your domain.