The first question: did you download the guide? A guide you have not downloaded needs a connection — nothing is cached just because you read it. Open the offline menu — the cloud icon Read offline on a laptop, Use offline in the reading tools on a phone — and check the book says Available offline. If it says Download for offline, that is the whole problem.
Downloads are per device. A book downloaded on your phone is on your phone. Download it again on your laptop if you want it there too.
Flashcards and questions need one online visit each. They download themselves the first time you open Flashcards or Tests while online — questions with a paid pass, flashcards for everyone. Open both once on wi-fi before a flight.
Things that never work offline, by design: Miles, and anything that has to reach us — buying, filing a guarantee claim, signing in for the first time on a new device.
If a download stalls, stay online and try Retry download. Downloads are sized in the menu before they start; a large book on a weak connection takes a while.
If your browser is in a private or restricted mode, the menu will tell you offline downloads aren't available there. Use a normal window.
Highlights made offline are not lost. They queue and sync the next time you are online — the toolbar shows a small syncing indicator while that happens.
