My device is iPad Air 2
The problem is: when I am reading books in airplane mode ( offline), I can read only 1-2 hours.After that all my books disappear and I can not find any books.When I trying to open iBook again, nothing is coming.But when I get Wi Fi connection or attach my iPad to the Mac,all my library becomes visible.All this problem occurs with all types of books( PDF,downloaded from store,downloaded from Mac).
My question is: Is something wrong with my iPad?
How to solve this problem?
Thanks.