Http Status Code 500 thrown when calling a controller action

Hi guys,

I am fairly new at MVC. Currently, I am trying to figure out how ASP.Net Web API 2 works. I have created 2 model classes and implemented the controllers using EF. I have also hosted the API on Azure. The problem when I test the API locally using IIS Express, I have no issues; everything works as expected, but when I hosted it and try to call action method from the controllers, I get an HTTP 500 error. Below is the code for my models and the controllers.

Student model

using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace ApiDemo.Models
{
    public class Student
    {
        [Key, DatabaseGenerated(DatabaseGeneratedOption.None)]
        public string Id { get; set; }

        public string FirstName { get; set; }

        public string LastName { get; set; }

        public string Major { get; set; }

        public string Minor { get; set; }
    }
}

Enrollment model

using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace ApiDemo.Models
{
    public class Enrollment
    {
        [Key]
        public int Id { get; set; }

        public string Course { get; set; }

        public string Section { get; set; }

        public string Professor { get; set; }

        [ForeignKey("Student")]
        public string StudentId { get; set; }

        public virtual Student Student { get; set; }
    }
}

StudentsController

using ApiDemo.Models;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Linq;
using System.Net;
using System.Web.Http;
using System.Web.Http.Description;

namespace ApiDemo.Controllers
{
    public class StudentsController : ApiController
    {
        private StudentDbContext db = new StudentDbContext();

        // GET: api/Students
        public IQueryable<Student> GetStudents()
        {
            return db.Students;
        }

        // GET: api/Students/5
        [ResponseType(typeof(Student))]
        public IHttpActionResult GetStudent(string id)
        {
            Student student = db.Students.Find(id);
            if (student == null)
            {
                return NotFound();
            }

            return Ok(student);
        }

        // PUT: api/Students/5
        [ResponseType(typeof(void))]
        public IHttpActionResult PutStudent(string id, Student student)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (id != student.Id)
            {
                return BadRequest();
            }

            db.Entry(student).State = EntityState.Modified;

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!StudentExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return StatusCode(HttpStatusCode.NoContent);
        }

        // POST: api/Students
        [ResponseType(typeof(Student))]
        public IHttpActionResult PostStudent(Student student)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            db.Students.Add(student);

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateException)
            {
                if (StudentExists(student.Id))
                {
                    return Conflict();
                }
                else
                {
                    throw;
                }
            }

            return CreatedAtRoute("DefaultApi", new { id = student.Id }, student);
        }

        // DELETE: api/Students/5
        [ResponseType(typeof(Student))]
        public IHttpActionResult DeleteStudent(string id)
        {
            Student student = db.Students.Find(id);
            if (student == null)
            {
                return NotFound();
            }

            db.Students.Remove(student);
            db.SaveChanges();

            return Ok(student);
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                db.Dispose();
            }
            base.Dispose(disposing);
        }

        private bool StudentExists(string id)
        {
            return db.Students.Count(e => e.Id == id) > 0;
        }
    }
}

EnrollmentsController

using ApiDemo.Models;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Linq;
using System.Net;
using System.Web.Http;
using System.Web.Http.Description;

namespace ApiDemo.Controllers
{
    public class EnrollmentsController : ApiController
    {
        private StudentDbContext db = new StudentDbContext();

        // GET: api/Enrollments
        public IQueryable<Enrollment> GetEnrollments()
        {
            return db.Enrollments;
        }

        //public IQueryable<Enrollment> GetEnrollments(string studentId)
        //{
        //    return db.Enrollments.Where(e => e.StudentId == studentId);
        //}

        // GET: api/Enrollments/5
        [ResponseType(typeof(Enrollment))]
        public IHttpActionResult GetEnrollment(int id)
        {
            Enrollment enrollment = db.Enrollments.Find(id);
            if (enrollment == null)
            {
                return NotFound();
            }

            return Ok(enrollment);
        }

        // PUT: api/Enrollments/5
        [ResponseType(typeof(void))]
        public IHttpActionResult PutEnrollment(int id, Enrollment enrollment)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (id != enrollment.Id)
            {
                return BadRequest();
            }

            db.Entry(enrollment).State = EntityState.Modified;

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!EnrollmentExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return StatusCode(HttpStatusCode.NoContent);
        }

        // POST: api/Enrollments
        [ResponseType(typeof(Enrollment))]
        public IHttpActionResult PostEnrollment(Enrollment enrollment)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            db.Enrollments.Add(enrollment);
            db.SaveChanges();

            return CreatedAtRoute("DefaultApi", new { id = enrollment.Id }, enrollment);
        }

        // DELETE: api/Enrollments/5
        [ResponseType(typeof(Enrollment))]
        public IHttpActionResult DeleteEnrollment(int id)
        {
            Enrollment enrollment = db.Enrollments.Find(id);
            if (enrollment == null)
            {
                return NotFound();
            }

            db.Enrollments.Remove(enrollment);
            db.SaveChanges();

            return Ok(enrollment);
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                db.Dispose();
            }
            base.Dispose(disposing);
        }

        private bool EnrollmentExists(int id)
        {
            return db.Enrollments.Count(e => e.Id == id) > 0;
        }
    }
}

DbContext

using System.Data.Entity;

namespace ApiDemo.Models
{
    public class StudentDbContext : DbContext
    {
        public DbSet<Student> Students { get; set; }
        public DbSet<Enrollment> Enrollments { get; set; }
    }
}

Locally, when I execute .api/Students, I get the expected result (this is assuming that locahost can be anything. But my model is hosted athttp://apidemo.azurewebsites.net. So when I execute something likehttp://apidemo.azurewebsites.net/api/Enrollments, I get a 500 error. Can anyone please help me out?

Thanks, you are the best!