This is likely tied to your device settings and is possibly related to a battery-saving function enabled on your Android device which is putting apps to sleep after a set amount of time.
To turn this off please try:
- Open the SETTINGS app. You will find the settings app on the home screen or apps tray.
- Scroll down and click on DEVICE CARE.
- Click on BATTERY options.
- Click on APP POWER MANAGEMENT.
- Click on PUT UNUSED APPS TO SLEEP in advanced settings.
- Select the slider to OFF.