You need to debug your app to check console error and get to know the exact issue:
https://websitetoapk.com/docs/debugging-with-chrome.html

Yes, Take a look at our APIs: https://websitetoapk.com/docs/pushadmin-api-access.html

@lgokul We will possibly add this feature in upcoming release by check cross compatibility with Google Play policies.

@nirmaldev , You can click on "Custom" in Splash screen option and choose your own PNG Image.

@LuisGarcia ,
Kindly raise a support ticket, forums is not intended for personal support issues:
https://websitetoapk.com/support/submit_ticket

Note that this warning is not related to piracy issue.

You can use Splash Image of 720x1280px to fit most of the devices.

@amosb , We thank you for your continuous support.

We would like to assure that we will make default firebase features available with upcoming releases. PushAdmin is to make it easier, not just for the purpose for charging users, as you can see our pricing for PushAdmin is very affordable just to cover up our service costs. :)

@amosb , We will surely make these new firebase notifications supported with upcoming releases.

@firzafadi You may get into legal trouble as well as it is major security concern also, along with that there might be unsafe codes injected in pirated copies.

We sincerely request you to kindly DO NOT use pirated copies and support our work and development by making a purchase for genuine copy.

Did you tried to debug to find exact issue by checking console logs:
https://websitetoapk.com/docs/debugging-with-chrome.html