web.config and membership - asp.net

Question

I have an Runtime error when I'm trying to perform login action or create user action on published website.
I have an ASPNETDB.MDF in appData folder, that created from ASP.NET Configuration.
I created new database in hosting, exported from ASPNETDB.MDF to a new database. I changed connection string.
Localy it work perfect, even with new connection string, but after i publish it i have an Runtime error.
I'm using asp login control and CreateUserWizard.
BTW, i've created some GridView and SqlDataSource to show all users, and it works.. But login and createWizard are not.
web.config
<configuration>
<connectionStrings>
<add name="ConnectionString" connectionString="Server=mssql3322.dotnet-host.com;Database=aspnetdb3;Uid=SomeUserNAme;Password=SomePassword;" providerName="System.Data.SqlClient"/>
</connectionStrings>
<system.web>
<roleManager enabled="true" />
<authentication mode="Forms" />
<compilation debug="false" targetFramework="4.0" />
</system.web>
</configuration>
BTW, i tryed to add membership provider to web.config and it didn't work even localy ))
UPD:
The error
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

Answer 1

Well for starters you could add the following to your web.config:
<configuration>
<system.web>
<customErrors mode="off"></customErrors>
</system.web>
</configuration>
This should allow you to get a more detailed error message about what is wrong. See if that get's you started down the right path. It should at least provide more information about what might be wrong.
Update - try this in your web.config:
<connectionStrings>
<remove name="LocalSqlServer" />
<add name="LocalSqlServer" connectionString="Server=mssql3322.dotnet-host.com;Database=aspnetdb3;Uid=SomeUserNAme;Password=SomePassword;" providerName="System.Data.SqlClient"/>
<add name="ConnectionString" connectionString="Server=mssql3322.dotnet-host.com;Database=aspnetdb3;Uid=SomeUserNAme;Password=SomePassword;" providerName="System.Data.SqlClient"/>
</connectionStrings>
Update - That worked! Here is a short explanation why:
By default the ASP membership classes use the connection string LocalSqlServer. The reason the code worked on your local machine is because the connection LocalSqlServer is defined in a machine level config file to point to the local sql database. When you published it the SqlDataSource/GridView worked because it was pulling the connection named ConnectionString that pointed to the correct server. However ASP membership was still trying to connect to the LocalSqlServer connection. The above config just ignores the machine level LocalSqlServer connection and defines it's own (and it leaves the ConnectionString one in place so that the GridView continues to function).