Non-existing handler on IIS


I am trying to get mediawiki working on a Windows Server 2012 with IIS8. When I browse to the site I get this error

HTTP Error 500.0 - Internal Server Error    scriptProcessor could not be found in application configuration  

At the bottom of the page a handler is listed with the name "Handler PHP54_via_FastCGI1". When I look at the handler mappings for both the whole server and the specific website I can't find a handler with this name however.

I have checked that there is a correct handler pointing to the php-cgi.exe of PHP7 but for some reason it doesn't work with my mediawiki. I am able to view the phpinfo.