If you find that your signboard that was once being displayed is no longer, it likely meant a loss of connection. This can happen during power outages, an interruption in service, or if Chromecast is installing an update.
Please try the following steps:
If all seems well, try recasting your signboard.
Reboot the Chromecast (How to Reboot)
Check your network connection. If it is down, please contact your Internet Service Provider.
Please note that Promota remembers what you had casted! Once you reconnect to the Chromecast, it will automatically display your board!