When using the Edge Security Pack (ESP) feature for Pre-Authentication to Microsoft Exchange 2013, you may experience an issue where logging out of Exchange Outlook Web Access is prevented by a browser pop-up message saying “Please close all browser windows to continue”. This is the result of a change in the Exchange product.
Historically, the logoff string was:
The new string is:
There should be a redirect set up from the old string to the new one, but this would not work with a load balancer as an intermediary.
In order to make it work properly, you will have to modify a file on the CAS server(s).
Please note, this applies only to Exchange 2013.
Navigate to the following file using a text editor:
(Local Drive)\Program Files\Microsoft\Exchange Server\V15\ClientAccess\Owa\web.config
Search for signoutkind.
Comment the line out by adding <!-- at the beginning and --> at the end. Save the file and reboot the server (an IISReset might not be sufficient).
In the Exchange Virtual Service on the LoadMaster, modify the SubVS for OWA and expand the ESP Options section. Enter /owa/auth/signout.aspx in the Logoff String field.