[Solved] Entity Framework Error: The underlying provider failed on Open in ASP.Net

Thank you for help me.

I find the problem and it was the connection string does not content password,

i don't know why but i add it manually and it work and this how the connection string looks like 

metadata=res://*/myModel.csdl|res://*/mymodel.ssdl|res://*/mymodel.msl;provider=System.Data.SqlClient;provider connection string="Data Source=server name;Initial Catalog=Database name;Persist Security Info=True;User ID=userId;Password=pwd;MultipleActiveResultSets=True"" providerName="System.Data.EntityClient"