I get the error: "provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified"

Programming, error messages and sample code > ASP.NET
This error usually indicates that your application is trying to connect to a SQL Express database. We do not support SQL Express databases on our servers. See this Knowledge Base Article.

You will have to upsize your SQL Express Database to SQL 2008 and change the web.config file connection string to point the SQL server.