Postfix Email Repair

I'm having trouble with my postfix email system, specifically, emails are not being sent or received.

the email was working fine, but lately we noticed unsolicited emails sent and during the DKIM setup, the email was missed up, it send transactional emails as usual but the webmail access always shows login failed and sending/receiving is not working, test email always return mail daemon error.

I am looking for an experienced postfix email specialist who can help diagnose and fix the issue. The ideal freelancer for this project should have:
- Proven experience with troubleshooting and solving email deliverability issues
- In-depth knowledge of postfix/dovecot email server system
- Familiarity with dedicated server environments

Your task will include:
- Identifying the root cause of the problem
- Implementing a solution that ensures reliable email delivery
- Performing any necessary configurations or updates to the postfix system
- Testing the system thoroughly to guarantee it's functioning as expected

Please only apply if you have the expertise and availability to work on this promptly.