I have made two unsuccessful attempt to enter the 2017 contest via the stocktastic website:

The first attempt kept claiming that I had not picked five different stocks which was patently not true but I had entered a different combination of name & email address (ie made a typo) from last year and I think that was the actual problem.

On the second attempt my internet connection went down when I hit the submit button.
Restoration involved my ISP rebooting their router for the entire apartment complex so I am loath to try it again.

Best Wishes
Paper Tiger