App notification blocked

[Timurr]

I'm facing a problem regarding to the notification,the system is not allowing me to unblock it and the block issue is only for a specific bank app I'm trying to use,can someone assist me regarding to this problem 

[karachikababa]

Background app closed then open it bank app

[Timurr]

Still bro doesn't work

[Timurr]

Have uninstall and install twice and have done clear cache still same problem