Help with mobile menu - Removing background picture

Hi, thanks for the theme its great!
I would like to know how to remove this background image that happens to be sneaking behind my mobile menu on all of my pages except the home page.

I think the image is the coffee stock one that came with theme. is the site for reference.

Thank you.

Hey there

Sorry but i see this message on the website:’s server IP address could not be found.

so, i can’t see the image but most probably it can be removed from the appearance >customize