I tested it too on my iPhone and same thing. However, I tried the episode after (3x5) and it's working fine so it seems to be something in particular with that file. As Barb said, probably a coding issue.
As in interim solution (I've tested it and it works) - Download the Puffin Web Browser (free in App Store) and go to VIPtv.net but make sure it's the desktop site. If it defaults to the mobile version go to the bottom of the page and click on desktop. Then log in and normal and watch the show.
