Code added after URL

This link might be helpful to you: https://www.labnol.org/internet/clean-wordpress-urls/19301/

If the problem still remains, kindly post it.

Thanks!

When changing the .htaccess file to the code they provide, the website shutdown and indicates a 500 error. The one added on the theme’s header.php doesn’t change anything. =/

Hey just checked your site & the suffix you were mentioning above is gone. Please verify.

Turns up this was an issue caused by the Cached Geolocation on Woocomerce.
Thanks!

Wow ! This just saved me sooooooooooooo much time. Thanks Summu89!