I bought iPad air last Sunday and I signed in with my Apple ID and I downloaded my apps that I purchased before. When I opened these apps, I couldn't open. I reset my iPad so many time but I can't open. I delete it and install it again, but can't. I also buy new apps that I haven't purchased but can't open. When I changed my brother's Apple ID and I buy app, I can open it. How to do? I have purchased many apps with my Apple ID and I can't use it in this iPad. Please help me to solve this problem.