When trying to print SSRS Reports from DRM you continue to get prompted for credentials.
Unlike Crystal reports, SQL reports use Windows Authentication to determine if you are allowed to see a report or not. When you turn on your computer in the morning and log in to your company domain with your username and password, those credentials follow you so that any program that can use Windows Authentication knows exactly who you are and what you have permission to do.
For example, if you log into the ‘Red’ domain as Sally and your reports reside on a server inside the ‘Blue’ domain, when you try to display one of those reports using DRM, the Blue domain does not know anything about Sally from the Red domain. It will deny you access.
To circumvent this, DRM allows you to use impersonation by entering the credentials for a user (i.e., Jim) in the Blue domain so that when you display a report using DRM, the report server will ignore the fact that you are Sally from the Red domain. It will assume that you are Jim from the Blue domain and will allow you access.
This is possible when displaying the SQL report in the SQL report viewer, printing the report, or exporting the report to file because in all three conditions, you are actually using the SQL report viewer or some part of it, which is what allows the impersonation to take place.
If you choose to display the same report in your web browser (bypassing the SQL report viewer all together) there is no way to impersonate another user because the web browser does not include this functionality. When the report server sees that you are logged in as Sally, it will display a login window wanting you to enter the credentials for a Blue domain user like Jim.