Local notifications in lockscreen

Hi:

First of all, I´m very new to Ionic…
I´m implementian a delayed local notification using https://ionicframework.com/docs/native/local-notifications
It works correctly, but when the screen is locked, even if I have define “lockscreen: true” the notification does not appear.
The only way to get it working correctly is enabling notifications in lockscreen through settings. Is possible to do it programatically? Or is is possible to ask the user, when the app runs at first time, to enable this permission?

Thanks in advance!