I think I solved it. They updated the app so you need to cast the video from a cellphone with the dailmotion app installed. If your TV doesn't support casting you'll might need a Chromecast and WiFi, but I have all that and got it to work. (This is the same way Twitch works.)
Ironically though I only needed to do this because Samsung's built in web browser can't access the Dailymotion website anymore. So it's always something!