Erro 26 - SQL SERVER

Amigos,

Estou fazendo um aplicação para rodar via web.

Utilizo banco de dados SQL Server Express, visual web developer.

Ocorre que no computador aplicação funciona porem via web não funcionar.

informa erro conforme anexo.

Acredito que esteja faltando uma forma de fazer com que aplicação funcione em um banco de dados via web, porem não sei como fazer e o que preciso.

ERRO:

Server Error in '/' Application.

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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)

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: 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)

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.