Proble with menu icon

Hi Andrea,
Can you please provide me your site URL and admin account (via private answer) for further checking?

I have checked your site on the iPhone 4 and seen that the menu icon still works fine for me without any problem.
To have better assistance, could you kindly provide me further information of the smartphone that you used for testing?

To resolve this issue please add following code to Dashboard / Appearance / Customizer / Custom code / Header code

<style>
@media (max-width: 1024px) { 
.navbar-toggle,
.nav-main,
.sidebar-primary {
top: 0;
}
</style>

Hope this helps!