The Screenly app starts itself when the device boots, so a screen recovers from a power cut on its own with nobody visiting the site.
Two device settings have to permit it first, and both are off on many devices. If a screen comes back to a home screen instead of your content after a restart, one of these is the reason.
Allow display over other apps
Screenly needs permission to put itself in front of whatever the device shows at startup. Without it the app starts but sits behind the launcher.
Open the device settings.
Find the app permissions for Screenly.
Enable the permission usually called Display over other apps.
Some manufacturers name it Appear on top, Draw over other apps, or Floating window.
Allow the app to start on boot
Android tells apps when the device has finished booting, and Screenly listens for that.
Some devices, and many consumer televisions, ship with a security or power-management app that blocks that boot message from reaching apps. That is usually the thing preventing an otherwise correct setup from coming back on its own.
Open the device settings and look for an autostart, startup manager, or permission manager.
On manufacturer skins this often sits under battery, security, or privacy rather than under the app itself.
Find Screenly in the list.
Allow it to start on boot.
The names and locations of both settings vary widely between manufacturers and Android versions. If you cannot find them, search the device settings for “autostart” and for “over other apps”.
Turn off sleep and power saving
Check the device’s own sleep and power-saving settings too. An Android TV in particular will often turn itself off after a period with no remote input, which looks like a Screenly fault and is not one.
Check it worked
Pull the power, wait, and plug it back in. The screen should return to your content without anyone touching a remote.
Test this before a screen is mounted somewhere awkward. A screen that needs a person to press a button after every power cut is the most expensive kind to run.