If your shop is inaccessible, check to see if the problem isn't related to the site itself. Shopify may be unavailable due to routine maintenance or a more serious problem. If it's maintenance, they'll normally send you an email ahead of time to let you know. If your Shopify page is 404 not found, you should redirect that page to a new page. Under Online Store > Navigation > View URL redirects > Create URL redirect > Save