HTTP Error 500 Internal server error

I’m sorry to hear you’ve run into issues.

Could you check your server error logs around the time when you experienced the issue, to find out more about the error?

If you don’t know how to access your server error logs, your hosting provider should be able to help.

You could also start by trying to increase the amount of memory allocated to PHP on your site, as it’s a common WordPress issue:
https://codex.www.ads-software.com/Editing_wp-config.php#Increasing_memory_allocated_to_PHP

Let me know how it goes.