We haven't been able to deliver the message to the recipient yet. It looks like your remote server's firewall is blocking the message from Office 365 because it's identifying the message as spam. Please review these details:
Recipient: {Recipient}
Email server name: {DestinationMailServer}
Email Server IP address: {DestinationIP}
Technical error message: {MessageDetail}
If the message isn't spam, let us know that if you contact support.
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We haven't been able to deliver it to the recipient yet because we can't connect to your organization's on-premises email ...
We haven't been able to deliver the message to the recipient yet because we can't connect to the recipient email server. ...
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