No message showing after registration

Hallo, others have posted this issue before. But I still can’t find a solution. After registration no message is shown on the registration page. Everything works perfectly fine, but the user won’t get any feedback on the registration page. I don’t use the form builder plugin. And I hope, you don’t want me to purchase is for such a simple task. Any help would be appreciated.

https://wordpress.org/plugins/simple-membership/