It might happen that the Phaser gets stuck in bootloader mode after plugging to power. In this mode, the main button for turning on the light is unresponsive, but the second (bottom) button starts the base colored light normally. If something like this happens, a firmware reupload is needed.
This is a companion discussion topic for the original entry at https://docs.sleep.urbandroid.org//faqs/phaser_v1-doesnt-connect-to-sleep-top-light-button-doesnt-work-bottom-light-button-works.html