Fix Exim Mail Server Issues

I need an experienced professional to resolve issues with my Exim mail server on WHM/cPanel. The primary problem is that emails are not being delivered, and I am receiving bounce-back messages. This issue is affecting server operations and needs urgent attention.

550 Please turn on SMTP Authentication in your mail client. mail-pl1-f173.google.com [209.85.214.173]:49447 is not permitted to relay through this server without authentication.



Key Requirements:
- Diagnose and fix the cause of emails not being delivered
- Analyze and resolve bounce-back message errors
- Ensure the mail server is properly configured and optimized for delivery
- Experience with WHM/cPanel and Exim mail server configurations

Ideal Skills and Experience:
- Strong background in server administration and email server management
- Expertise in Exim mail server and WHM/cPanel
- Ability to troubleshoot and resolve email delivery issues
- Familiarity with analyzing server logs and error messages

Please reach out if you have the skills to help resolve this issue promptly.