This issue mainly occurs when there is a problem with the application pool .i.e when the application pool is stopped . Can you please check the application pool status and start it , if its stopped . To check the application pool MyComputer--> RightClick --> Manage check in the manage ..
We found the same issue . Do you have any solution ??
User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; GTB7.5; chromeframe/28.0.1500.95; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; InfoPath.2; Tablet PC 2.0; .NET4.0C; .NET4.0E; 3M/MSIE 8.0)