It means the webpage you are trying to reach cannot be found on the server.
This error can occur if the URL is typed incorrectly, the page has been removed, or the link is broken.
You can check the URL for typos, try searching for the content through the site's search function, or navigate from the homepage.
Yes, most websites have a contact or support page where you can report broken links.
It's unlikely without intervention; typically, it requires the website owner to fix the link or restore the page.