Error getting value from 'ServerVersion' when trying to JsonConvert.SerializeObject

I have a very basic code using Entity Framework to get a model in my MVC C# .NET Controller.

var myModel = myContext.MyData
                .Where(m => m.ID == 1)
                .FirstOrDefault();

string json = Newtonsoft.Json.JsonConvert.SerializeObject(myModel);

When I try to run this code, I get an error:

Error getting value from 'ServerVersion' on 'System.Data.SqlClient.

... If I press 'Continue', the view says:

[InvalidOperationException: Invalid operation. The coection is closed.]

Whats wrong?? What does SQL have to do with this? The same error comes if I do this in the View instead of the Controller.

The underlying coection used by myContext seems to be closeddisposed.

Check where are you creating the DbContext and be sure that when you're calling your code it's in a valid state.