DevOps, CI/CD and Automation

Found the cause... In my WEB API I was returning a string but APEX seems to be expecting an HTTP response.
So changed:
public string Put(Department dep)
{
try
{
string query = @"
update dbo.Department set DepartmentName=
'" + dep.DepartmentName + @"'
where DepartmentId="+dep.DepartmentId+@"
";
DataTable table = new DataTable();
using (var con = new SqlConnection(ConfigurationManager.
ConnectionStrings["EmployeeAppDB"].ConnectionString))
using (var cmd = new SqlCommand(query, con))
using (var da = new SqlDataAdapter(cmd))
{
cmd.CommandType = CommandType.Text;
da.Fill(table);
}

           **return "Successfuly updated row!";**  
       }  
       catch (Exception)  
       {  
           **return "Could not update row!";**  
       }  
   }  

to

public HttpResponseMessage Put(Department dep)
{
try
{
string query = @"
update dbo.Department set DepartmentName=
'" + dep.DepartmentName + @"'
where DepartmentId="+dep.DepartmentId+@"
";
DataTable table = new DataTable();
using (var con = new SqlConnection(ConfigurationManager.
ConnectionStrings["EmployeeAppDB"].ConnectionString))
using (var cmd = new SqlCommand(query, con))
using (var da = new SqlDataAdapter(cmd))
{
cmd.CommandType = CommandType.Text;
da.Fill(table);
}

           **return Request.CreateResponse(HttpStatusCode.OK, table);**  
       }  
       catch (Exception)  
       {  
           **return Request.CreateResponse(HttpStatusCode.NotFound, "Could not update row!");**  
       }  
   }  

Hope it helps someone!