You can use a Chrome extension to unblock websites:
This is the most common block. Chrome blocks pages with invalid security certificates. how to unblock a page on google chrome
Sometimes Chrome remembers a site is "bad" even after it’s fixed. You can use a Chrome extension to unblock
Note: If you are the organizer, go to family.microsoft.com > Find the child's account > Content Filters > Web Browsing > Add the site to "Allowed sites." go to family.microsoft.com >