UAPP Pauses Play when screen is shut off

[toshu]

I have been running UAPP with an Android TV box for years, and recently loaded it on to a Zidoo Z9X media player. 
In both instances whenever I turn off the monitor/TV, which is connected via HDMI, the playing music is paused. 
I have checked Settings in UAPP and haven't found anything to prevent this.
Any help would be appreciated since I don't want or need the TV to be on.

[dwrae]

Please see if you can turn off battery optimisation for the app in the Android battery section or Android Settings app -> Apps -> UAPP.
Other than that, please ask the manufacturer of the device.