A 404 Page not found error means the Start.me page URL you're trying to access doesn't exist. The page may have been deleted, the URL may be wrong, or your extension may point to a page that no longer exists.
Your New Tab extension points to a deleted page
If you see a 404 every time you open a new tab, your browser extension is configured to load a page that no longer exists. To fix this:
Click the Start.me icon in your browser toolbar.
Click the cog icon to open Extension Options.
Select a different page from the dropdown.
Your browser homepage URL is a direct page link
If you set a specific page URL (like https://start.me/p/DFKKFJf) as your browser homepage and later delete that page, you'll get a 404 on every browser launch.
Fix: Change your browser's homepage to https://start.me instead. This always loads your first available page and avoids broken links. See How do I set Start.me as my default start page? for details.
Someone shared a broken link with you
The page owner may have deleted or unshared the page since they sent you the link. Contact the person who shared the URL and ask for an updated link.