Dear customer,
It seems that there might have been an accidental touch on the screen. We suggest wiping the device to prevent any moisture or dirt from accidentally affecting the display. It's possible that this issue could be due to the relatively humid conditions in your city. Please ensure that the environment where Spark is located is kept somewhat dry and avoid exposing it to water.
Thanks,
Wency
Netro Support
Could you please unplug the power, and then plug it back in to see if it resolves the issue?
Thanks,
Wency
Netro Support