OWA - Enter Network Password dialog box missing

[cowitzer]

Hi,

When users(who are login to the domain in the office) enter their mailbox name at the default.htm screen, the OWA inbox screen appears without 1st prompting to enter the network username and password.

If users(not in the office) try to access OWA remotely, they will get the "OWA was unable to get to your inbox." screen because the Enter Network Password dialog box did not appear(I guess).

Am I missing something? What should the directory setting/permission be?

Thanks in advance for any suggestions.