When Microsoft Exchange Server 2016 is installed on a server that is running Windows Server 2016, an administrator cannot manage regional settings for other users through the Exchange Control Panel (ECP). In this situation, the Regional Settings page is not displayed, and the administrator receives an HTTP 500 error message that contains the following exception detail:
TypeInitializationException in static constructor Microsoft.Exchange.Management.ControlPanel.RegionalSettingsSlab..ctor()