I recently had the same issue.
The connection string lacks every piece of information that Entity Framework expects. You must put the connection string supplied by SQL Azure into the
provider connection string
EF's connection string's argument.
<add name="MyConnectionString" connectionString="metadata=res://*/Model.Model.csdl|res://*/Model.Model.ssdl|res://*/Model.Model.msl;provider=System.Data.SqlClient;provider connection string="[PUT SQL AZURE CONN STRING HERE]"" providerName="System.Data.EntityClient" />
The metadata from your own project must be used. That information was taken from an EF project that was created using an existing database.