Changing from Forms-based to Integrated Auth in Exchange
When changing your OWA/ECP directories from Forms-based Authentication (FBA) to Integrated Authentication in Exchange, you may start getting a blank page after the authentication redirect.
If this happens, make sure you enabled another Authentication provider on the sites (Windows Integrated or Basic if using SSL).
Set-OwaVirtualDirectory "owa (Default Web Site)" -WindowsIntegrated:$true
Set-EcpVirtualDirectory "ecp (Default Web Site)" -WindowsIntegrated:$true
Now, the redirect should trigger the Authentication prompt.