I had the same problem and solved it through Live Chat. I had tried using my mobile phone with wi-fi and then three different browsers. Each time I got the same "oops" message. I was advised to try my phone without the wifi and it worked straight away and asked for the code.
Like other members my smart stick was fin for a week and whilst it starts and takes me through to my TV as soon as I choose a channel the 'Oops something is wrong, cannot download video comes up. I have re-bootesd several times but stick gets quite warm but is still faulty