If the app freezes on launch or shuts down right after opening, start with the basics: force-close it and reopen. If that doesn't help, clear the cache — on Android go to Settings → Apps → Duolingo → Clear Cache. iOS users should delete and reinstall the app entirely. Make sure your OS version meets the minimum requirements; outdated firmware is a surprisingly common culprit.
This usually points to a connection issue rather than the service itself. Check whether other apps load content normally. If they do, try switching between Wi-Fi and mobile data — sometimes one channel is throttled or unstable. Logging out and back in also helps reset the session and clears stuck data.
Completing a lesson and seeing no XP credited is frustrating. This typically happens when the internet drops mid-lesson. Duolingo requires a stable connection to sync results. Finish lessons only when you have reliable connectivity; offline mode is limited and doesn't always sync cleanly upon reconnect.
If you hear nothing during listening tasks, first check your device volume and make sure the app isn't muted in system sound settings. On mobile, toggle the mute switch. In desktop browsers, confirm the site has permission to play audio — some privacy extensions block it silently.
If daily reminders stop showing up, go to your device notification settings and confirm Duolingo has permission to send alerts. On iOS, also check Focus modes — they often silently block notifications from specific apps.