What are some common reasons for the "open() failed: Datei oder Verzeichnis nicht gefunden" error in PHP?

The "open() failed: Datei oder Verzeichnis nicht gefunden" error in PHP typically occurs when the file or directory specified in the open() function does not exist. To solve this issue, you should double-check the file path and ensure that the file or directory exists before attempting to open it.

$file_path = "/path/to/file.txt";

if (file_exists($file_path)) {
    $file = fopen($file_path, "r");
    // Perform operations on the file
    fclose($file);
} else {
    echo "File not found.";
}