What if you have a very old WP site and suddenly you decide to update everything and in the middle of everything you suddenly get a white screen.

The Great White Screen of Dead. No error messages are displayed and the console is empty as hell. The only thing you get in the web tool of your web browser is 500 Server error.

Ok, that is something. So you will need so FTP access. Then go to the wp-content and look for the debug.log file. This on records all the apache errors that your server is getting. Open it and go to the end of the file. There check with the time you have tried to access for the site and see the log from this time. Its telling you what is causing the problem. In most cases it is a problem with the new update of the plug-in, an error  due to old php version on your server or something like this.

To fix it – just go to wp-contnet/plugins/the_problemed_plugin and rename its folder or just deleted it. An that is should fix it.