Same with me.com (I think this is the same issue)
Final-Recipient: rfc822;[user][at]me.com
Action: failed
Status: 5.0.0 (permanent failure)
Remote-MTA: dns; [17.172.36.44]
Diagnostic-Code: smtp; 5.1.0 - Unknown address error 550-'5.7.0 Blocked - see https://support.proofpoint.com/dnsbl-lookup...216.154.195.49: [user][at]me.com' (delivery attempts: 0)
Reporting-MTA: dns; c60.cesmail.net