To mitigate the risks associated with MTA-STS misconfigurations, consider the following recommendations:

- **Start with Testing Mode:** Begin MTA-STS implementation in `testing` mode to monitor potential issues without affecting email delivery:
  ```
  version: STSv1
  mode: testing
  max_age: 86400
  mx: mail1.example.com
  ```

- **Implement Progressive Max Age Values:** Use shorter max_age values initially and increase gradually, the recommended value is 1-2 weeks.

- **Regular Policy Monitoring:**
  * Monitor MTA-STS reporting data for policy failures
  * Review SMTP TLS connection logs
  * Verify HTTPS certificate validity regularly
  * Check DNS record consistency across authoritative servers

- **Security Best Practices:**
  * Use strong SSL certificates (2048-bit RSA or better)
  * Enable HTTP/2 for policy serving
  * Implement proper HSTS headers on the policy host
  * Maintain proper SPF, DKIM, and DMARC alignment

- **Operational Procedures:**
  * Document MTA-STS configuration in your DNS change management process
  * Create incident response procedures for MTA-STS-related issues
  * Maintain backup mail servers in policy configuration
  * Test policy updates in a staging environment first

- **Planned Changes Strategy:**
  1. Start with policy in `testing` mode
  2. Gradually increase `max_age` value
  3. Monitor reporting data for issues
  4. Switch to `enforce` mode after successful testing period
  5. Maintain documentation of all changes and their impacts

These recommendations help ensure a robust and secure MTA-STS implementation while minimizing the risk of email delivery disruptions.