Merge pull request MicrosoftDocs#6448 from dariomws/patch-214

Added note about availability in 21vianet to Search-UnifiedAuditLog.md and Search-MailboxAuditLog.md

Author: chrisda

exchange/exchange-ps/exchange/Search-MailboxAuditLog.md

@@ -56,6 +56,8 @@ Search-MailboxAuditLog [-Mailboxes <MultiValuedProperty>]
 ## DESCRIPTION
 The Search-MailboxAuditLog cmdlet performs a synchronous search of mailbox audit logs for one or more specified mailboxes and displays search results in the Exchange Management Shell window. To search mailbox audit logs for multiple mailboxes and have the results sent by email to specified recipients, use the New-MailboxAuditLogSearch cmdlet instead. To learn more about mailbox audit logging, see [Mailbox audit logging in Exchange Server](https://docs.microsoft.com/Exchange/policy-and-compliance/mailbox-audit-logging/mailbox-audit-logging).
 
+This cmdlet is available in Office 365 operated by 21Vianet, but it won't return any results.
+
 You need to be assigned permissions before you can run this cmdlet. Although this topic lists all parameters for the cmdlet, you may not have access to some parameters if they're not included in the permissions assigned to you. To find the permissions required to run any cmdlet or parameter in your organization, see [Find the permissions required to run any Exchange cmdlet](https://docs.microsoft.com/powershell/exchange/find-exchange-cmdlet-permissions).
 
 ## EXAMPLES

exchange/exchange-ps/exchange/Search-UnifiedAuditLog.md

@@ -46,6 +46,8 @@ The Search-UnifiedAuditLog cmdlet is available in Exchange Online PowerShell. Yo
 
 If you want to programmatically download data from the Microsoft 365 audit log, we recommend that you use the Microsoft 365 Management Activity API instead of using the Search-UnifiedAuditLog cmdlet in a PowerShell script. The Microsoft 365 Management Activity API is a REST web service that you can use to develop operations, security, and compliance monitoring solutions for your organization. For more information, see [Management Activity API reference](https://docs.microsoft.com/office/office-365-management-api/office-365-management-activity-api-reference).
 
+This cmdlet is available in Office 365 operated by 21Vianet, but it won't return any results.
+
 You need to be assigned permissions before you can run this cmdlet. Although this topic lists all parameters for the cmdlet, you may not have access to some parameters if they're not included in the permissions assigned to you. To find the permissions required to run any cmdlet or parameter in your organization, see [Find the permissions required to run any Exchange cmdlet](https://docs.microsoft.com/powershell/exchange/find-exchange-cmdlet-permissions).
 
 ## EXAMPLES