What it 500 Internal Server Error: It means the server encountered an unexpected issue that caused it to fail in fulfilling the request.

Causes: Error with the server configuration files, or corrupted plugins that affect server files.

Fix 1

Replace the .htaccess file code with a new one with the Basic WP in https://wordpress.org/support/article/htaccess/

Fix 2

Increase Memory Limit PHP Variable – How to edit PHP variables

Fix 3

Deactivate plugins – How to deactivate plugins manually

Like all technical areas, errors will happen. It’s important to note a few things regarding using the fixes in this article:

1. Check DNS & make sure everything is proper before resorting to changing files.
2. When handling any files, make sure to follow this guide: How to handle WordPress files