Event ID - 4007

Event Id4007
SourceMSExchangeActiveSyncNotify
DescriptionMessage delivery to the host host name failed while delivering to the remote domain name for the following reason: text The SMTP verb which caused the error is text. The response from the remote server is text.
Event InformationAccording to Microsoft:
Cause:

This Warning event is logged when Exchange cannot deliver a message to a remote host. The event description should specify the reason for the failure.
Some common reasons for this Warning event include the following:
The connection was dropped by the remote host.
The remote SMTP service rejected AUTH negotiation.
The server trying to deliver the message cannot access the message delivery information in the message.
An SMTP protocol error occurred.
The server that is trying to deliver the message cannot connect to the remote server.
If a smart host has been specified in the properties of the SMTP virtual server, this event can be logged if the smart host is unreachable for any reason.
Note:This event can also be logged when the Mail Host Filtering feature of Sybari Antigen Antivirus Software is enabled. See User Action for more information.
User Action :
To resolve this error, try one or more of the following:1.
Make sure that the SMTP virtual server and SMTP connector are correctly configured. For example, on the properties of the SMTP virtual server, you should make sure that the smart host specified is a valid, functional smart host.
2.Look for DNS name resolution problems.
3.Check any events that come before or follow this event message to determine whether they explain the underlying reason for the message delivery failure.

Note:
If you are using the Mail Host Filtering feature of Sybari Antigen Antivirus Software, disabling that feature may resolve this issue.
Reference LinksMessage delivery to the host host name failed while delivering to the remote domain name for the following reason: text The SMTP verb which caused the error is text. The response from the remote server is text.

How to configure the SMTP connector in Exchange 200x

When to create SMTP connectors in Exchange 2000 and later

How to Configure a SMTP Virtual Server

How to Troubleshoot Basic TCP/IP Problems

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