>Hi,
>
>A customer reported a problem where some of the emails sent by my ASP.NET application are rejected. The error message is:
>

>The server response was: 4.4.62 Mail sent to the wrong Office 365
>

>
>I noticed that all emails that were rejected have a common domain. For example "@country.gov"
>
>I don't know how email servers work. But do you think the organization IT should whitelist this domain ("@country.gov") in the email server?

This is one of the most frequent issues reported by clients. It's usually caused when the recipient's mail server has marked the sender as a spammer and is routing the email to a spam folder or just blocking it.