While hosting a webapplication on local server, I came across following issue in configuration file:
Parser Error Message: Unrecognized attribute 'xmlns'
This issue is because your webapplication is built in higher version that .NET version that IIS is using. To see which version your IIS is running on: Right click "Default Web Site" > Properties > ASP.NET tab > See ASP.NET Version dropdown box. This might be showing version : 1.1
You need to change this version to current .NET version on which your application is built.
To do so go to Visual Studio command prompt: type aspnet_regiis -i
Wait for some time and your done..