In Exchange 2016 when you try and access OWA or the Exchange Admin Center (EAC), you might be presented with the following error:
The webpage at https://wwwmail.domain.local/owa might be temporarily down or it may have moved permanently to a new web address.
This is due to a cipher and/or hash issue and can be resolved with some 3rd party tools like iiscrypto. You can select the "Best Practice" option in the tool and then reboot your server.