Why can't I see the country databases inside my plugin?

Inside the Magic Page Databases screen in the top right-hand corner you should see a drop-down box with the words United States in. If you click on that box then you will see all the other countries that MPP has databases for.

unable to see magic page database dropdown

If you can not see the dropdown box then this could be for a number of reasons.

Your server is not running PHP 7.4 as a minimum, preferably PHP 8.0
Your WordPress is not up-to-date
You have your browser zoomed out and the dropdown is off the screen
It could be due to a Theme Conflict. Some themes will stop the drop-down showing. Install one of the WordPress default themes and then take another look
It could be due to a Plugin Conflict. Try disabling each of your other plugins 1 by 1 then check the dropdown to see which of your plugins are causing the issue.