Sophia here from Shopify. Welcome to the Shopify Community!
I understand how important it is that your website is consistently accessible to customers as well as to you, so I'm happy to help you sort this out.
I am able to access kzeniya.com on desktop (using Google Chrome 89 as shown in the first screenshot below), though I am having trouble viewing the store from my mobile device.
Using Google Chrome on my Android phone, I run into an error message that reads "This plug-in is not supported", and some of the menu items (like PRESS and COLLECTIONS) resulted in another message, reading ERROR THROWN Call to undefined function nggCreateGallery()".
I was eventually able to get the home page to load correctly by first navigating to CONTACT and then clicking on your logo to get back to the home page, though I recognize that's not sufficient and some customers might leave when they see that the home page hasn't loaded correctly on the first try.
Can you tell me the name of your theme (under Online Store > Themes in the admin) as well as which you've installed any apps on the store? It would also be helpful to know if the theme code has been edited at any point. This information will help us narrow down what could be causing the loading issues. Thank you!