“The requested resource or page cannot be found.” Yes, the dreaded 404 error. This is the message that your visitors will see when the page they were looking for no longer exists. Not great for the user experience or building trust with potential new customers. Seeing a message like this will likely cause them to look elsewhere. They can certainly try refreshing the page, but if the page was recently taken off the server, refreshing or confirming the URL is not going to help.
From the user’s perspective, the issue with an HTTP 404 error is that it does not tell them where they can access the page, or similar resource, they were searching for, making it even more frustrating. From the viewpoint of a web developer or webmaster, if a page is inadvertently taken down, it is likely it will go unnoticed for some time.