Problem with an item purchased

I have issue with an item which i purchased from codecanyon - Binder its a dating app clone

As pee the author i have followed the documentation but i couldn’t find a solution to fix the issue. There is no issues with the code but for the app to work properly i would have to setup the API part which connects the admin panel and my app. I would have to access the URL to get the api files as per the documentation. But when I access this url it comes into an error code 500. Author says that its the issue with the server. But i have use the same on different server with cpanel, plesk and other but i couldn’t solve this

I anyone could help me to solve this will be much appreciated

Documentation: Binder - Documentation

Please follow the last second topic on the documentation

Product: Binder - Dating clone App with admin panel - Android v20.1 by qboxus