Microsoft Exchange Active Sync "HTTP error 500.24 - Internal Server Error" and "An HTTP 500 response was returned from IIS7"

 Applies to  : Microsoft Exchange Server 2016

Problem: Mails on Mobile Devices are not synching, from internal/external networks.

further, diagnose open https://testconnectivity.microsoft.com and got below error " An HTTP 500 response was returned from IIS7"

I tried to access Microsoft Active Sync Virtual directory from web browser "https://example.contoso.com/Microsoft-Server-ActiveSync" and got the below error " HTTP Error 500.24 - Internal Server Error"

RESOLUTION :

1) Open IIS Management console

2) Select, Default Website, and Navigate to the Active Sync virtual directory.

3) Open Advance Settings and Copy Path of the Virtual Directory.

4) Go to the Virtual Directory path and Find "Web.config" file. ( Example Path : %Exchange Server Installation Directory%\ClientAccess\Sync\web.config" ) 

5) Open "web.config" file in Text Editor and Find "impersonate". ( Make Copy of the original file prior to editing )

6) Setup value, impersonate=True to False.

7) Save File and Restart IIS Server.

References : 

https://social.technet.microsoft.com/Forums/en-US/e60ebbf2-f8d2-403f-8d20-aada110bfd72/activesync-problem-http-500-response?forum=exchangesvr3rdpartyappslegacy 

https://helpcenter.gsx.com/hc/en-us/articles/115006225328-Exchange-2010-CAS-Check-ActiveSync-500-Internal-Server-Error

https://www.azure365pro.com/exchange-activesync-returned-an-http-500-response-internal-server-error/