How can I troubleshoot a '502 Bad Gateway' error when using urllib?

First, verify the target website is actually up and accessible from a different browser or device. If it is, the problem likely lies with the proxy server. Check your proxy settings in your script (if you're using one) for accuracy. Consider trying a different proxy server if possible. If you're not using a proxy, ensure your internet connection is stable. Finally, the server might be temporarily overloaded; try again later.