I cannot find any 'beginner mode'. They didnt mention it either, just insisted that it is my sd card telling me it is not compatible, then showing me a list where mine is clearly on the list as compatible. They were quite dismissive and bot really helpful at all.Did DJI help you check Beginner mode? You were stumped by that when it was first mentioned.
Come to think of it, I'm not seeing Beginner mode in Fly, but I don't have the RC/AC connected at the moment.