Open menu disappearing

Hello there,

I need to send this to a client today and i can’t seem to make the mobile menu work and I don’t know why!

In the Designer, when opening the menu it works fine, but in real time it disappears. Please see Screen video: I’m sure it’s something simple i have missed.

My navbar had a fixed position, so i put it to the default relative position again and inside a fixed div, but it hasn’t changed the issue.

Thank you so much for your help!

Here is my site Read-Only: LINK