After transferring a Wordpress site to a new hosting, the mobile version broke down - what should I do?

Question

WordPress

Hello.
I transferred a site with an adaptive theme to a new hosting and the adaptive version of the site stopped working for me, moreover, on all themes. The theme itself is responsive.
The mobile theme works only if you go to the admin panel from your smartphone (the admin panel is properly mobile) and enable the theme setting. That's when it works, in other cases, the site (online magazine) and the publications inside it are displayed as from a PC.
The plugin, with which I make up publications, also refuses to show the mobile version to mobile phones.
What could go wrong? What can I do to make mobile work again?
The site itself is here