The two most common situations in which this symptom occurs are:n - A badly configured server or application returns an HTTP error but still displays the page. Users will not notice the error but Google will consider the website to be unavailable and can remove it from the index.n - The scale of website traffic depletes the resources available in the hosting service. The website will load for some users, but everyone above a specified limit (e.g. number of processes) will see an error message (e.g. `HTTP 500 Internal Server Error`).