Why won't my SM1 Slim Mechanical Keyboard turn on or hold a charge?

If your SM1 Slim Mechanical Backlit Bluetooth Keyboard (ST-KSM1LT-EN, ST-KSM1DK-EN) will not power on or drains quickly, check the charging first.

How to get the SM1 to power on and hold a charge

Charge the keyboard using the included USB-C cable plugged into a computer or a wall adapter. On the SM1, the spacebar LED flashes slowly when the battery is low, so charge until the flashing stops.
Watch the charging light while the keyboard charges. If no light appears, try another USB-C cable and another power source.
Make sure the power switch is on, and set to the correct mode, whether Bluetooth, wireless receiver, or wired.
Test the keyboard in wired mode. If the keyboard works wired but not wirelessly, factory reset the keyboard by pressing Fn + Left Ctrl + Delete, then pair the keyboard again.
Confirm you are within range and that the paired device's Bluetooth is on.