Problem with Newsomatic API key – Invalid registration code

Hello, I recently purchased **Newsomatic – Automatic News Post Generator Plugin** from Envato (purchase code: xxxxxx). When I try to use the plugin, it always shows: “Invalid registration code submitted” or “Invalid NewsomaticAPI key.” I also created a NewsAPI.org account and inserted my API key, but the plugin still does not accept it. Could you please check and tell me how to fix this issue? Thank you very much for your support. Best regards, Anila Maci