Hi! I understand you're having trouble turning on the Astrill VPN client while in China, and the switch just stays off when you try to enable it. Let's work through this together.

First, just to clarify:
- Are you using the latest version of the Astrill VPN app on your Android 10 device?
- When you try to turn it on, does it show any error messages or just fails silently?
- Are you connected to Wi-Fi or mobile data when attempting this?
- Have you been able to use Astrill successfully in China before on this device?

Often in China, VPNs can face IP blocks or restrictions. The issue where the switch won’t turn on might be due to the particular VPN server IP being blocked by the Chinese network. Here’s what we can try:

1. Reconnect to a different server:
- Open your Astrill app and look for the option to switch VPN servers.
- Try selecting a different server location or a server labeled for China or optimized for China use if available. A different IP address might work because the one you were using could be blocked.

2. Enable Stealth VPN or Obfuscation mode:
- Astrill offers stealth or obfuscated VPN protocols designed to bypass strict censorship.
- Go into your app’s settings and enable stealth mode or a similar privacy feature. This often helps VPN traffic look like regular internet traffic and avoid blocks.

3. Check your network settings:
- Make sure you don’t have any active proxies or unusual DNS settings that might interfere with Astrill.
- You can try switching your DNS to Google DNS (8.8.8.8) in your device settings if you haven’t tried that yet.

4. Restart your device:
- A simple reboot sometimes resolves low-level network software conflicts preventing the VPN from connecting.

Since you’re on Android 10 with WebKit browsing, the above steps should be easy to perform. If these do not resolve the issue, it might be worth uninstalling and reinstalling the app to ensure a clean setup.

If you want, I can also guide you through more advanced settings or troubleshooting depending on what you observe after trying these steps.

Let me know how it goes or if you see any messages when switching the VPN on!

Are you satisfied with this initial guidance?

It is on my computer, I am not sure if it is the latest version. It worked well before but it suddenly stopped working

Thanks for the extra info! Since you're using Astrill VPN on your computer in China and it suddenly stopped working, it’s possible the app version might be outdated or there could be an issue triggered by a recent update or network block.

Here’s a step-by-step plan to troubleshoot this on your computer:

1. Check for Updates:
- Open your Astrill VPN client on the computer.
- Look for an option like "Check for updates" in the app menu (usually under Help or Settings).
- If an update is available, install it. New versions often fix connection issues or bugs.

2. Restart the VPN Client and the Computer:
- Exit Astrill completely (right-click the system tray icon and select quit/exit).
- Restart your computer.
- Launch Astrill again and try to connect.

3. Reinstall Astrill:
- Uninstall the current Astrill application from your PC.
- Download the latest version from the official Astrill website: https://www.astrill.com/download
- Install the fresh version and log in with your credentials. This can fix corrupted files or old configurations causing the problem.

4. Switch VPN Protocol or Server:
- In the Astrill app, try changing the VPN protocol (e.g., from OpenVPN to Stealth VPN or WireGuard if available).
- Also, switch to a different server location since certain IPs can get blocked.

5. Run the Client as Administrator:
- Right-click the Astrill shortcut and choose "Run as Administrator".
- Sometimes, permission issues prevent the VPN from toggling on.

6. Check Network Restrictions:
- Since you are in China, the Great Firewall might have blocked the VPN.
- Using Stealth mode or obfuscation is crucial here, and sometimes you may need to contact Astrill support for the latest working servers or configurations optimized for China.

If you follow these steps and still encounter trouble turning on the VPN, a useful trick is to open Astrill, hold down the "CTRL" key, click on the HELP tab, then select "TAP Drivers Repair" to fix driver issues that can disable VPN switching4.

Would you like me to guide you through any particular step? Also, I can help you check if your version is up to date or assist in downloading the latest installer.

Are you satisfied with this troubleshooting plan so far?