It should reconnect (and will usually turn on). It might not be working well, another power cycle might do it or you may need to reposition it or your router. Or it may have connected but has received a new IP from your router, if your phone is connected to your 5GHz band in a dual band router it may not be able to find the bulb as it connects to the 2.4GHz band. You might try enabling remote access and/or connecting your phone to the 2.4GHz band.