Aria here, I'm on the Social Care team at Shopify.
Thank you for providing the ticket number. I have now fixed your domain, your site is working again. Although your A record was set up correctly, your CNAME/subdomain was missing (www). You can find out more about how to manage your domains in this guide.
While I was fixing your domain, I noticed it is not set to automatically renew. This means you will need to make sure you log in and manually renew your domain if you want to keep it after the first year. If you would like to set it up to Auto-renew, go to Online Store > Domains > Manage > Auto-renew then tick the box.
Let me know if you need anything else. How are you getting on with your store setup?
I just took a look at your store and it seems to be functioning normally:
Do you have a screenshot to show the error at your end? Which browser are you using? What happens if you use a different browser?