When you use Internet Explorer 11 to access the Exchange Control Panel (ECP) in a Microsoft Exchange Server 2013 environment, you can't successfully perform the following operations:
- Create a new send connector or change the existing send connector
- Add secondary SMTP address to a user mailbox
This issue occurs because the ECP pop-up window request isn't handled reliably by Internet Explorer.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.