I have a Plesk 11.5 server that someone made changes to in IIS to allow web site users to turn the sending of detailed error messages on and off from a web.config file. Unfortunately now none of the sites will send detailed error messages to the browser no matter what is done. The person that made the changes to IIS did not document them properly and cannot tell me what exactly they changed. None of the obvious settings have made an effect on the problem.