Issue Sender address rejected: Access denied; Error code is 554 5.7.1

[Shareef Ahmmed]

Server operating system version

Centos 7

Plesk version and microupdate number

Plesk Obsidian 18.0.74 Update

I am facing an issue in Plesk where emails sent from our domain are being rejected. Although the domain has already been whitelisted, the issue persists. The error message is: “Sender address rejected: Access denied (Error code: 554 5.7.1)”. Could you please suggest any solution to resolve this?