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Title
Mail flow from Notes to Office 365 no longer working -
Description
Mail flow was working from Notes to O365 but now it is not. From O365 to Notes still works.
Domino console reports;
Router: Error transferring message <MessageID> via SMTP to <CMN-FQDN> 503 5.5.2 Need rcpt command
Actual Error found in the SMTP log when SMTP logging enabled;
DEBUG CMN.SmtpProtocol.logging [Proxy 1]: Message Number [##] on Thread [##] from Domino (ServerIp:Port) to Exchange (ServerIP:Port): Sending response: 550 5.7.1 Service unavailable; Client host [PublicIP] blocked using Blocklist 1; To request removal from this list please forward this message to delist@messaging.microsoft.com (file://delist@messaging.microsoft.com/)
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Cause
The IP address appears to be on a Microsoft blocklist -
Resolution
RESOLUTION 1
To be removed from this block list Microsoft asks that you find and forward a copy of your version of the message below to delist@messaging.microsoft.com
DEBUG CMN.SmtpProtocol.logging [Proxy 1]: Message Number [##] on Thread [##] from Domino (ServerIp:Port) to Exchange (ServerIP:Port): Sending response: 550 5.7.1 Service unavailable; Client host [PublicIP] blocked using Blocklist 1; To request removal from this list please forward this message to delist@messaging.microsoft.com (file://delist@messaging.microsoft.com/)
RESOLUTION 2
Check Office 365 Service Health section to see any incident reported in regards to mail routing.