What are common reasons for PHP include errors like "failed to open stream: No such file or directory"?

When encountering a PHP include error such as "failed to open stream: No such file or directory," it typically means that the file being included cannot be found at the specified path. This can occur due to incorrect file paths, file permissions, or the file simply not existing. To solve this issue, double-check the file path in the include statement to ensure it is correct and that the file exists at that location.

<?php
include 'path/to/file.php';
?>