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()
This problem occurs because Windows 2016 contains several sublanguages that have the same Language Code Identifier (LCID) property. Some LCIDs may not be currently valid.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.