I just recently changed the password on my iTunes Apple ID. It works fine everywhere except for the Mac App Store and iBooks on my Mac running El Capitan build 15A262e). iTunes works fine. I created a new user account on the Mac, and it signs in fine there. I've tried creating a new keychain, deleting Mac App Store preferences and cookies, and I can't get this to work on my main user account. My other Apple IDs sign in fine. The iTunes one is the only one causing me problems. Any ideas on how I can resolve this?