Guys I've been having the same problem for a long time now. I keep reporting it and have tried every possible fix. The thing is, all other apps play videos on my Ipad fine so it doesn't matter what you do, it's down to the developers making a hash of the app. Plain and simply incompetence on their part so don't stress yourself trying to sort it. I have now given up on the game because if Nordeus with all the money they are making from tokens can't invest some of that by employing developers who know what they're doing then it's their loss. Screwing up the app so that we can't get boosters isn't going to make us put our hand in our pocket. It just turns people like myself away from the game and onto something else.
Celtic
Level 24
8 trebles
23 league wins
8 cup wins
22 Champions leagues won.
As you can see from my stats I have been a dedicated player but I'm through banging my head against a brick wall trying to get boosters for my team
Celtic
Level 18
16 Leagues
16 Champions Leagues
5 Cups
5 Trebles