Delete method is not working in web api core

Iam using web api core in my application get and post method is working fine

these are code

 public class DepartmentController : Controller
    {
        [HttpGet]
       [Route("api/Departments")]
        public List<Department> Get()
        {
            DepartmentDbContext Db = new DepartmentDbContext();
            List<Department> Departments = Db.departments.ToList();
            return Departments;

        }
        [HttpPost]
        [Route("api/Departments")]      
        public string Post([FromBody] Department department)
        {
            DepartmentDbContext Db = new DepartmentDbContext();      
                try
                {
                    Db.departments.Add(department);
                    Db.SaveChanges();
                    // return department;
                    return "Added Successfully";
                }
                catch (Exception)
                {
                    return "Record Not Added";
                }    
        }
}

the above code working fine and also worked fine in postman also

but delete method is not working

here is the code

[HttpDelete]
[Route("api/Departments")]
public int Delete(int id)
{
    DepartmentDbContext Db = new DepartmentDbContext();
    try
    {
        Department dept = Db.departments.Where(x => x.DepartmentID == id).FirstOrDefault();
        Db.departments.Remove(dept);
        Db.SaveChanges();
        return 1; 
    }
    catch(Exception)
    {

        return -1; 
    }
}

this code is not working in postman also

how to solve this

Regards

Baiju