Error 404

Hello
I’m having problems when I activate the “WordPress Language” option.
The description points out that it is necessary to contain the language packs for WordPress. I verified that the necessary languages are installed, however, when this option is activated, it translates part of the link, preventing a particular page from being found.

http://qualyair.com/en_US/ > work
http://qualyair.com/pt_BR/ > work

http://qualyair.com/en_US/product/new-ac-condenser-toyota-camry-avalon-venzalexus-es35-cm112028-8846007060/ > work
http://qualyair.com/pt_BR/produto/new-ac-condenser-toyota-camry-avalon-venzalexus-es35-cm112028-8846007060/ > does not work

I wait for help… tks

https://ww.wp.xz.cn/plugins/multilanguage/

The page I need help with: [log in to see the link]