Silent Fail?

I have the following simple file:

echo '1';
$link = mysqli_connect('localhost', 'right_name', 'right_pw');
echo '2';

Up until a few days ago, this would have worked. But suddenly, this fails. All this prints to the screen is the number 1. What might the reason for this be?

The server’s PHP configuration changed so that errors are no longer displayed on screen.