logo on sticky menu

Do you have a navigation logo set in the Page Header settings for that page?

As for the size, try this:

.navigation-logo img {
    width: 230px;
}

Tom, that's right! There was still the "deleted" image .... Now the logo is visible on all pages! Thank you so much!!

I entered this code <i class = "fas fa-envelope"> </ i> in the Navigation Label of the contact, but a square appears instead an envelope.

How can I align the main menu with logo?

fas is Font Awesome 5, which isn't in the theme yet.

Try: fa fas fa-envelope for now.

Thank you for all your help!

You're welcome :)