Hello, I have been trying to email myself several kindle books to open in my kindle app. I receive them on my iPad, however when I try to click the attachment file in the email, it just says cannot open this attachment. I have done this before with other books and it worked fine. It is just recently that I cannot open any mobi files. The files are a little bigger, does it take time for them to load? Anyone have any ideas on why this may have changed?