Cognos Analytics 11.1.7
Microsoft Windows 2016 server
When browse to IBMCOGNOS site you get a error message. This after a upgrade of cognos on a old server.
You change the Cognos Application pool to use localsystem as identity, but it did not help.
If you browse to controller test site; http://servername.domain.com/ibmcognos/controllerserver/ccrws.asmx or if you try http://servername.domain.com/ibmcognos/bi/v1/disp , then it works.
Check the folder C:\inetpub\wwwroot for any web.config file.
This can be like this:
Rename the web.config file and restart iis with dos command : iisreset.