500 Internal Server Error

Have you spoken to your webhost about this?
What were his suggestions?
Did you follow these suggestions succesfully?

== == == also:

Step 1: [first check if the plugins or updates caused the problem]

1. Use FTP to access your site
   bv. https://filezilla-project.org/download.php
2. rename all plugins by putting a ‘0’ in front of each plugin -folder;
   ../wp-content/plugins
3. Check if the access / ‘normal functioning’ has been restored
4. If so: one-by-one, remove the ‘0’, checking every time to see if the problem re-occurs.
5. when the problem re-occurs, you’ve found the source of the problem; Delete and find a similar plugin that works with your site
6. alternatively: FTP:Delete; Then download and install / activate a NEW version of the problematic plugin and see if this works.

The first thing to do is look at the error logs on your server. Witha 500 error it’s impossible to know what the problem is without doing that as that’s the only place that the log messages are stored. When you find out what the errors are, then you can see about fixing them. Before then there’s really nothing else that you can do because you don’t know what’s wrong.