This is caused by the extra protection applied to the adoption process. Back in the old version, just after you adopt an adoptable, you can keep refreshing the page to get that certain adoptables again and again. In the new version, we've added this security layer to prevent people from doing that. Thus, they have to go back to the adoption page to adopt an adoptable.
If you want to make your own adoption page, make sure you do the following:
1. Initialize/reinitialize a session
PHP Code:
<?php
session_start();
2. Set a session value, 1, with the key being "allow"
PHP Code:
$_SESSION['allow'] = 1;