Work down this list. The first three fix most of it.
1. Reload the page. Genuinely. A single failed request can leave a panel empty or a button dead, and a reload re-fetches everything.
2. Are you offline? Check the badge in the reader toolbar. Plenty works without a connection, but plenty does not — see "Offline isn't working".
3. Is it a private or restricted browser window? Offline downloads and saved settings need ordinary site storage. In a private window the app will tell you what it cannot do. Use a normal window.
4. Try the other device. If it is fine on your phone and broken on your laptop, that is a browser or extension problem, and it tells us a lot. Ad blockers and strict privacy extensions are the usual culprits.
5. Check the address. If the page says it does not exist, see "When a page says it doesn't exist" — the usual cause is being signed in as a different account.
6. Update your browser. We support current versions of Chrome, Safari, Edge and Firefox. A browser several years old will show real layout faults.
When it is content rather than the app
A wrong answer key or a contradictory explanation is not a bug in this sense — use Report a problem on the item itself, which sends us the exact question. See "Reporting a wrong question or explanation".
Telling us
Email [email protected] with:
what you tapped, what you expected, and what happened;
the address in your browser's bar, in full;
a screenshot — the single most useful thing you can send;
your device and browser.
That set is usually enough for us to reproduce it in one go. We aim to reply within one business day, and anything that stops you studying goes to the front of the queue.
