You cannot open a rights-protected e-mail message in Microsoft Office Outlook Web Access (OWA) by using the Rights Management Add-on (RMA) for Internet Explorer.
This issue may occur when OWA uses form-based authentication. RMA does not support form-based authentication.
To work around this issue, save the rights-protected e-mail message as a file on the hard disk. Then, open the file.
Note Rights-protected e-mail messages use the .rpmsg file name extension.
Form-based authentication requires that the source URL appears in a browser window. However, RMA does not support displaying the source URL in a browser window. RMA expects the URL to be a binary data stream that does not appear in an HTML window.