Not able to enable migrations through Nuget Package Manager

Question

I am trying enable-migrations in console but getting this error. I am getting this error, please help anyone.

The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception.

This is my program.cs file

public class Employee
{
    public int EmpID { get; set; }
    public string Title { get; set; }
    public DateTime Date { get; set; }
}
public class BlogDbContext : DbContext
{
    public Dbset<Employee> Employees { get; set; }
}

class Program
{
    static void Main(string[] args)
    {

    }
}