No mobile menu on small screens andf smartphone

woodyf4u

I have already created several websites with the T4 Template Framework.
So far I never had any problems with the mobile menu (hamburger menu).
But on this website I don't get a mobile menu on screen.
I compared the settings with websites where it does work.
But I don't see the difference that leads to the solution.
What could be the cause?

woodyf4u

Oops, my bad.
Earlier I had disabled font awesome in css.
That's why the hamburger icon didn't show up anymore.