Scenario:
LS242 Brightsign player has lost an internet connection, player reboots and sits at at the default media screen or a black screen.
From BrightSign development:
When the LS424 product line was launched, LS424 players did not have a supercapacitor to keep the real-time clock (RTC) in the players running if there was no other power source. If you power cycle these players, they will lose their configured time settings, and (unless the player can reach a local/remote timeserver) it will not be able to play day-parted presentations at scheduled times or communicate with SSL servers including the BrightSign Network.
The most recent version of the LS424 now includes an RTC with supercapacitor that backs up the clock settings when it is power cycled.
The LS424 model which contains the RTC Supercapacitator starts with characters TFF.
This is a hardware limitation from Brightsign.