php sha256 example

echo hash('sha256', $_POST['ppasscode']);

$hash = hash('sha256', 'hello, world!');
var_dump($hash);

Could this be a typo? (two Ps in ppasscode, intended?)

$_POST['ppasscode'];
I would make sure and do:

print_r($_POST);
and make sure the data is accurate there, and then echo out what it should look like:

echo hash('sha256', $_POST['ppasscode']);
Compare this output to what you have in the database (manually). By doing this you're exploring your possible points of failure:

Getting password from form
hashing the password
stored password
comparison of the two.