To fix proxy server errors on your internet connection, try the following steps:

1. Restart your modem/router.
2. Check your internet connection.
3. Check the settings on your modem/router.
4. Check if the network address translation (NAT) service is enabled.
5. Check if you need to update your proxy server.
6. Check if the web filtering service is enabled.
7. Clear your web browser's cache.
8. Reset your DNS settings.
9. Check your computer’s firewall settings.
10. Uninstall any third-party firewall software.