Sticky header doesn’t work

Hello,

I’m having some issues with my sticky header. It doesn’t work, on any page. I’m using a child theme of sydney, and i can see that the header gets the class “.sticky-active” upon scrolling. Also the main class “.sticky-always” has “position: sticky” in it’s style, but it doesn’t seem to turn sticky, or be sticky. How could i fix this?

(Here is my site)

Thanks in advance,
And have a nice day ??

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