Hey vedathemes, thank you for your fast reply. The URL is the one in my first post.
Maybe it was my mistake, the Widget is working very well now.
I’ve tried the URL on the settings page: https://XXXXXXXXXX/wp-admin/options-general.php?page=pp-options and from the begining the “error” appeared.
At second try I’ve created a widget (the correct way of usage) and it worked out of the box with the exact same link, so everything is fine. Thank you for the great plugin!
Cheers, Christian