Fix My Linux Email Server

I'm seeking an experienced Linux sysadmin to troubleshoot and fix issues with my self-hosted email server.

The server is currently not functioning properly, affecting email operations.

Key requirements:
- Expertise in managing and troubleshooting Linux-based email servers
- Proficient in diagnosing and resolving email delivery issues
- Familiarity with email server software (Postfix, Dovecot, etc.)
- Ability to ensure server security and prevent future outages

Please provide a brief overview of your experience and approach.