Mobile site appears different on site and redirect domain

Hello! My original Wordpress site is ericarascon.com. When I visit the site on mobile devices, it's mobile ready and looks great. I bought the domain deeplyrootedwellness.com and pointed it to ericarascon.com. On desktop, everything is the same. Great! But when I visit deeplyrootedwellness.com on mobile, it's not mobile ready. It has the desktop layout with ultra-tiny font. The main menu is also tiny and difficult to navigate. (I've tried Android and iOS.) I would like deeplyrootedwellness.com to look the same as ericarascon.com on mobile. Please advise. Thanks, Erica