Returned mail: see transcript for details

From: MAILER-DAEMON@ip-172-31-11-86.ec2.internal
Domain: IP info ip-172-31-11-86.ec2.internal
MX-server: IP info ip-172-31-11-86.ec2.internal
Size: 1039 Bytes
Create: 2025-03-08
Update: 2025-03-14
Score: 0
Safe: Yes

The original message was received at Fri, 7 Mar 2025 22:58:37 -0500 from localhost [127.0.0.1] ----- The following addresses had permanent fatal errors ----- (reason: 550 5.7.606 Access denied, banned sending IP [52.4.236.121]. To request removal from this list pleas...26655 AS(1427) [CY4PEPF0000FCC0.namprd03.prod.outlook.com 2025-03-08T03:58:38.465Z 08DD5992A8C1C437]) ----- Transcript of session follows ----- ... while talking to southernplcs-com.mail.protection.outlook.com.: >>> DATA ... User unknown