Cannot use manage.aspx in asp.net website

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C#

Hello,

I use C# ASP.NET to build a website with membership and role involved.
Since ASP.NET has its own login module, I just stick to the default module.
However, when I run my website through Visual Studio 2012, I can open this manage.aspx page to modify my password. Once website is published and I try to open this page, it will run a while and say "A network-related or instance-specific error occurred while establishing a connection to SQL Server."
Look like it did not talk to database.
Any advice?
Thanks.

What I have tried:

I did not use webpage to create new user or role but using ASP.NET Configuration in VS2012.