Android TV has different versions of firmware on the Android system. Sometimes, the OptiSings will not auto starts when the Android TV reboots. There is a default app that will block any app from auto-starting.
TCL Android Smart TV:
Safety Guard app will disable the OptiSgins app auto starts. Here is a step-by-step on how to enable it.
To provide permission on "Auto Launch Safety Guard":
Safety Guard -> Permission Shield -> Auto Launch -> Auto Manager: Closed; And also provide permission to OptiSigns player by changing it to Open.
Google Chromecast with Android TV:
To enable the OptiSigns auto start:
Settings -> Apps -> Special app access -> Energy optimization -> OptiSigns app -> Disable it
Then go to "Turn screen on" in the Special app access -> OptiSigns app -> Enable it.