About the 403 error for Japanese URLs when using All In One WP Security

2024-06-16

How to fix the 403 error for Japanese permalinks in an environment with the WordPress security plugin 'All In One WP Security' installed

This is a note about how I got stuck with a 403 error for Japanese permalink pages in an environment with the WordPress security plugin All In One WP Security installed, and the solution I found.

Displays 'Access denied. You do not have permission to view this page. HTTP ERROR 403'

Conclusion
Other Possible Causes

Conclusion

It was fixed by turning off 'Advanced String Filter' from the 'WP Security > Firewall' settings.

Advanced String Filter

That's all.

Other Possible Causes

When it comes to 403 errors in WordPress, the cause is usually 'WAF', and I suspected it first this time too.

However, no WAF was detected...

Next, I reviewed the .htaccess file.

Checking for incorrect syntax or unintended access restrictions.

Also, try 'disabling all plugins'.

This time, it was fixed here, so I was able to narrow down the cause.

Next, you might try...

Switching to a default theme
Checking permissions for each file and directory
Migrating to a different environment (e.g., local) (If that fixes it, the server is the cause, or WP itself is buggy)

and so on...