The recipient's email system rejected the message due to a Sender Policy Framework (SPF) issue. SPF is a setting that helps filter unwanted messages.
The recipient's email server (outside Office 365) returned an error. The sender's message appears to violate a policy setting ...
The recipient's email server (outside Office 365) uses the spamrl.com spam block list and it suspected your message is spam. ...
The recipient's email system is using the McAfee (MXLogic) email filtering service. When Office 365 tried to send the message ...
The recipient's email system is using the Mimecast email filtering service. When Office 365 tried to send the message to ...
The recipient's email system rejected the message due to a Sender Policy Framework (SPF) issue. SPF is a setting that helps ...
The recommended value for 'MinUserDc' registry entry on server '{0}' isn't configured correctly. This value should be between ...
The registry setting 'Send Mail Immediately' is not configured correctly to prevent email from leaving your outbox for '{0}'. ...
The registry value 'FCheckTcpTimedWaitDelayEntry' on registry key 'System\CurrentControlSet\Services\Tcpip\Parameters' isn't ...
The registry value 'MaxUserPort' on registry key 'System\CurrentControlSet\Services\Tcpip\Parameters' isn't set to '{0}'. ...