Here is one of the many ways of resolving the 500 Internal Server Error.
Have you just installed or updated a plugin and got the 500 Internal Server Error message? If you can not access the backend dashboard to delete it, don’t worry you can log in to your hosting and delete it their.
Log in to your hosting account and select FileManager from Website.
Next go into your crashed websites folder and go to wp-content > plugins.
Now select the plugin you updated or installed.
Select the red ‘X‘ at top, above the search bar and the plugin will be deleted, now check back to your website to see if it is back up.