I may advise you to check the error logs. And to see exactly what’s causing the 500 Internet Server Error while trying to update the plugins. If you are using cPanel at the actual host, you should find an icon named ‘Errors’ where you can check to see if any errors were logged. In case you are unable to find them, contact your web host, provide them with your IP address and ask them to check the error logs. Based on their findings, you can work on a fix. If there’s anything else that I can help you with, please let me know.