Hi there – thank you for the very detailed description. That really helps. I think your tablet’s Firefox simply got “stuck” with an old or broken sync token, even though you signed out and back in. Here’s a clean fix that should get it working again. You won’t lose your bookmarks or passwords (they are safely stored in your Mozilla account), but you will lose any open tabs and temporary settings on the tablet itself. 🔧 Step-by-step fix (Samsung tablet) 1. Remove the tablet from your account (on the web) · Go to https://accounts.firefox.com/ on any device. · Sign in, then click “Connected services” (or “Devices”). · Find your Galaxy Tab S10 FE+ in the list and click “Disconnect” (or the trash icon). · Don’t worry – this only removes its permission, not your data. 2. Clear the Firefox app’s local data (this is the key step) · On your tablet, go to Android Settings → Apps → Firefox → Storage. · Tap “Clear data” (sometimes called “Clear storage”). · This will sign you out and reset Firefox completely, but won’t affect your account’s cloud data. 3. Restart the tablet (a normal restart is fine). 4. Open Firefox and sign in again · Open Firefox, go to Settings → Sign in, and enter your Mozilla account credentials. · Once signed in, make sure Sync is turned ON for at least one item (bookmarks, passwords, etc.). 5. Wait a minute or two – your data should start flowing in. 📌 Why this works The problem usually happens when the local sync engine gets confused – it thinks it’s connected, but the server sees an old/invalid session. Signing out alone doesn’t always erase that broken state. Clearing the app data completely removes that local confusion and forces a fresh, clean connection ❓ Still not working? · Check if your tablet’s date & time are set to automatic (Settings → General management → Date and time). An incorrect time can break encrypted sync. · Make sure your tablet has a stable internet connection (Wi-Fi or mobile data). · If possible, update Firefox to the latest version from the Google Play Store or your official source. You’re definitely not alone – this happens sometimes, but the steps above fix it in 90% of cases. Let us know how it goes!