Translate my menu

Hi,

I have an issue to translate my menu.

Whatever I try to translate my main menu (which is English) in French, it get a 404 page: https://screencast.com/t/570ZWChv

Could you let me know if I have to setup something on the theme please?

Basically,  if you visit the blog now you will see that my menu is the same in French or English. I just want to have the translate in French.

In addition, I would like to add a way for the user who is on mobile, to change the language from a top menu (right now, it’s at the bottom of the website on mobile).

I have activated the WPML option on the theme, activated the language on Menu, on WPML settings, but I have nothing.. Any idea of the issue?

Thanks in advance for your help!