1) Isolate the network
- Switch networks (Wi‑Fi ↔ 4G/5G).
- Try another Wi‑Fi.
2) Isolate browser/session
- Private window.
- Sign out/in.
- Clear cache/cookies.
3) Desktop sync checks
- Check if sync is paused.
- Restart the client.
- Check disk space and plan storage.
4) Permissions
- For shared links/files, request access from the owner.