An error has occurred when Open CRM Webpage

I have a big problem. I Installed CRM 2011 on Windows server 2008 r2 and SQL 2012.

It warked after I made a customization. I try to open it I found the error appeared as

" An error has occurred.

Try this action again. If the problem continues, check the Microsoft Dynamics CRM Community for solutions or contact your organization's Microsoft Dynamics CRM Administrator. Finally, you can contact Microsoft Support."

I am trying to solve it.kindlly I need help