Hello, I have a domain with an external of ispconfig server mail server. I have configured dns with external mx entries. I have wait for dns propagation, more than two days, reestart postfix and amavis. Mail is never delivered: Action: failed Status: 5.4.6 Diagnostic-Code: X-Postfix; mail for domain.com loops back to myself I need to send mail from ispconfig server to a domain configured on same ispconfig but with external mail server. Any trick to solve it? Very thanks.