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Event ID: 1056 Source: POP3Connector

Level
Description
The message <id:{<ID>}> can not be delivered. The error code is: <error code>.
Comments
 
It appears that this is caused by e-mail without a specified sender in the "from" or "to" field. You can look at the mail which is stored in C:\Program Files\Microsoft Windows Small Business Server\Networking\POP3\Failed Mail to see the missing information and resend, or just delete it as it is likley either spam or a failed mail notification.

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