The FastCGI Process Exited Unexpectedly

Hi,

I have a Windows Server 2016 running under Azure and have installed PHP 7.1 in c:\php with php.ini running therein.  I created a PHP_FastCGI Handler mapping to c:\php\php-cgi.exe and am now at the point where I need to activate a custom plugin within Wordpress.  I ensure that IIS_USRS and Network Service have full control to c:\inetpub\wwwroot\wordpress.  My default document type is .php in IIS as well.

Upon activation of the Wordpress custom plugin, I received the error The FastCGI Process Exited Unexpectedly. 

What additional steps must be taken to ensure an error-free configuration?  Thanks for your help and guidance.