problem with menu : plugin not display when user connected

Hello Jacques.

Like you, I use the twenty seventeen theme. I encounter an anomaly on mobile.

Indeed, the menu appears well on the mobile screen and drop-down sub-menu too, but when I click on the items (any of the sub-menu) it sends me to a “no results” page with an element of research.
I did follow your explanatory video.
What is the error that I may have encountered when setting up the plugin according to you?

Thank you.