Most common reason for this error is a routing issue. Consider the following network diagram as an example:
In this above example, every email composed by the user goes to Exchange before reaching Xeams. Assume your domain name is
and the user composes the request for report to
Exchange gets this email before Xeams, it will return an error since there is no user matching this email address.
There are two ways to solve this problem:
- Configure Xeams as the SMTP server in user's email client. This however, may not be practical for every environment.
- A better approach is to create a dummy sub-domain. For example,
reports.acmecorp.com. Add an MX record in your
DNS server referring to Xeams' IP address. Then, ask the user to send the request to
instead. When Exchange gets the message, it will be forced to perform an MX lookup on the domain, which will lead it to deliver the message