Symptoms
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()
Cause
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.
Resolution
Exchange Server 2016
To resolve this issue, install Cumulative Update 10 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the terminology that Microsoft uses to describe software updates.
