Various issues that you may run into are: white screen, your demo import fails, empty page content and other similar issues which are all related to low PHP configuration limits. The best way is to increase the PHP limits of hosting account.
To work with SEOLounge, please ensure that you are running WordPress 4.7 or higher, PHP 5.6 or higher, and MySQL 5.6 or higher. We have tested it with Mac, Windows and Linux. For better hosting experience, we recommend using https://wordpress.org/hosting/.