Andrew, Thanks for point out about API white list. but it doesn't solve the problem.
Here is more detail about my problem
My app works fine in Joget v6. So I try to import it to Joget DX7. After testing, I found that I cannot download PDF from Jasper report pdf view form. So I setup a simple app to test what went wrong with these step
- Create new app then add a Form, a List and a UserView
- I use a form and list to create List view page and put view ( also add view (hidden) for testing ) link

3. 2 links above point to Jasper report in UserView. Link number 1 works fine and I can download pdf file in pdf view page. But from link number 2 which point to JasperReports number 2, I can view report page but download pdf button in that page give me a blank page. And the problem solved if I just set "Hide From Menu" off. But for most use-case, I want to left any JasperReports in hidden category section. User can access it form list page. It also need parameters to get proper data associate with that record to display.

4. Below is the JasperReport page and the download PDF link that work only in not-hidden Category

I'll continue with v6 until this problem is solved. Here is my test on Joget cloud https://artitp.cloud.joget.com/jw/web/userview/test/view/_/61F65DFDDEC3433BB19CF7DFA2910C1C