To resolve the "No connection to server" error with the TeleGuard application, follow these detailed steps:

1. Check Internet Connectivity:
- Ensure your device is connected to the internet. You can do this by opening a web browser or another app that requires internet access. If you encounter issues, try switching between Wi-Fi and mobile data.

2. Restart the App:
- Close the TeleGuard app completely and reopen it. This simple action can resolve temporary glitches that may be causing the connection issue.

3. Update the App:
- Go to the Google Play Store and check for any available updates for TeleGuard. Updating to the latest version can fix bugs and connectivity problems.

4. Restart Your Device:
- Sometimes, restarting your Android device can clear out any software issues that impede connectivity. Turn off your device, wait for a few seconds, and then turn it back on.

5. Check Server Status:
- There may be server issues affecting many users. Look for announcements on official TeleGuard or social media pages discussing server status or ongoing issues (TeleGuard - Support - [learn more]).

6. Network Change:
- If you are using the same network as your AirMessage server or another server that has been known to cause conflicts, try switching to a different Wi-Fi network or mobile data (Reddit Discussion - [learn more]).

7. Clear App Cache:
- Go to your device settings, find Applications, locate TeleGuard, and select 'Storage.' From there, choose 'Clear Cache' to remove any stored data that may be causing connectivity issues.

8. Reinstall the Application:
- Uninstall TeleGuard and reinstall it from the Google Play Store. This process can eliminate any corrupted files that may have been installed.

9. Contact Support:
- If none of the above steps work, reach out to TeleGuard Support for direct assistance. They can provide specific troubleshooting steps for your account or device (TeleGuard - FAQs - [learn more]).

By following these steps, you should be able to troubleshoot and resolve the connection issues with TeleGuard.