Error in roleswhen user login to account in Asp.net

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C#

ASP.NET

Dear,
Following Error occurs while trying to login the application deployed on hosting server, while on the other hand it works perfectly fine on the local machine.

Any help/guidance will be highly appreciated.

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: 


Line 72:             string type = cmd.ExecuteScalar().ToString();
Line 73: 
Line 74:             if (!Roles.RoleExists(type)) Roles.CreateRole(type);
Line 75:             if (!Roles.IsUserInRole(lgnUser.UserName, type)) Roles.AddUserToRole(lgnUser.UserName, type);