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2017-12-08T14:17:41+00:00 September 27th, 2011|Office 365, Windows|

You receive the error below when attempting to login to Outlook Web Access (OWA). In an environment with multiple Client Access (CAS) servers where CAS proxying is being used:

image

Solution:

On the target CAS server, Ensure that Windows Integrated Authorisation is the only the authorisation method enabled on the OWA and ECP virtual directories.