Getting Android Version Specific Issues

[doconcall]

I am using this module for pushing notifications in an Android notifications.
It is very important that the notifications pop up asap according to the app requirements.
It was working perfectly till yesterday but suddenly yesterday, there was an issue and only phones with a few versions of android could get the notifications and mainly Android 8 did not receive the notifications and all.
If anyone has ever faced an issue like this, please help me out asap as it is very urgent for us to solve this problem.