Immediate Fix
If your Galaxy S25 Ultra is repeatedly showing an “Account Session Expired” notification, the fastest solution is a manual cache purge of the Samsung Cloud and Account services.
Force Stop and Clear Data
Navigate to Settings > Apps. Tap the “Your Apps” filter icon and toggle on “Show system apps.” Locate Samsung Account.
Select Storage, then tap Clear Cache and Clear Data. Restart your device immediately. This forces the One UI system to request a fresh OAuth 2.0 token from Samsung’s servers.
Update Android System WebView
Many login prompts on the S25 Ultra rely on the WebView component. Go to the Google Play Store, search for Android System WebView, and ensure it is updated to the latest version. A stale WebView version often fails to render the modern authentication handshake.
Technical Explanation
The “Session Expired” error on the Galaxy S25 Ultra typically stems from a mismatch between the local JSON Web Token (JWT) stored in the device’s Secure Enclave (Knox) and the server-side session state.
On the S25 Ultra, aggressive battery optimization settings can occasionally hibernate the com.osp.app.signin process. When this process is killed while trying to refresh a background token, the synchronization link breaks, resulting in a persistent login failure loop.
Alternative Methods
If the standard UI settings do not resolve the issue, you may need to interface with the device via the Android Debug Bridge (ADB) to reset the specific identity package responsible for account management.
ADB Command Fix
Connect your Galaxy S25 Ultra to a PC with USB Debugging enabled and execute the following command to reset the account manager:
adb shell pm clear com.samsung.android.mobileserviceFix Comparison Matrix
Use the table below to determine which troubleshooting step to prioritize based on your specific symptoms.
| Method | Success Rate | Difficulty | Data Loss Risk |
|---|---|---|---|
| Manual Cache Clear | High | Low | None |
| Network Settings Reset | Medium | Moderate | Wipe Wi-Fi Passwords |
| ADB Package Reset | Very High | High | None |
| Samsung Account Re-add | High | Low | Temporary Sync Pause |
Finally, ensure that your Date and Time settings are set to “Automatic.” The Galaxy S25 Ultra uses time-based security protocols; even a 30-second discrepancy between your device clock and the global NTP servers will cause an immediate session expiration.