English doesn't work

Hi, sorry for my poor english !! I am french 😉

I upload MLS on my Website Network, I use 3 language French, spanish, and english. It work well for French and spanish but when I select english it don’t accept it and switch to french !!!

If you know what can it be, thank you !!!

https://ww.wp.xz.cn/plugins/multisite-language-switcher/