Network unavailable error when screen is off or after exiting the browser whilst downloading files I am using  UC browser mini , Iam using jio internet . When my phone's screen turns off or I exit the browser UC browser mini, the downloading file says that network unavailable what is the reason? How can I fix that?

My phone is Samsung galaxy grand prime 4g
In the advanced WiFi settings, the keep WiFi on during sleep option may be the cause.