Ad issues

Good evening. I'm writing in regards to video ads in game. I have watched several ads but I'm never granted the rewards because I cannot go back into the game without restarting it. I am very familiar with games like this and know many are on a time setting, but that time will be roughly 5-10 mins with no X to close or working back button. I've tried other settings on my phone from other user recommendations but nothing is working.