Exchange 2010 OWA authentication issues?
If you are not reading the step-by-step installation guide (any of them) and relying on Exchange 2010’s “pre-requisites” check, you may have an issue with OWA when done.
Basically when the setup program is checking the Pre-requisites for CAS, it doesn’t check to ensure you have the correct authentication protocols installed.
This can be remedied by adding them as follows;
I also enabled the Windows Authentication, just for good measure.
Post-install no need to force an IIS restart (I think it does it as part of the install TBH), just refresh your OWA logon page and login as you want 🙂