Where can I find error_log file(s)?

While your site is being processed, the code may generate “errors” – notifications, if you like. There are different types of errors, and depending on the nature of your site (production or dev), you’ll want easy access to them.

Where to find error_log file(s) depends on the host and configuration.

You may start within the 'wp-admin' folder, and then the next level up.

Also, you might find them on the root of your webhost in files like "error_log" or "php_error_log". Or maybe in a logs folder beside your public html folder. 

Failing that you'll need to check with your host...

This blog article here may help.