Sometimes the Philips bridge sends data to Lightbow that it cannot understand, and even though you are properly connected and authenticated, lights or schedules go missing. Here are some things you can do to troubleshoot.
1) First, try the usual gotchas—is WiFi enabled and are you connected to the same local network as your lights?
2) Scroll to the bottom of your lights list and make sure your bridge isn't showing a lock (unpaired) icon. If it is, just tap that row, look for the "Pair" button, and touch-link your bridge
3) If you're still seeing issues, make sure you're running Lightbow 3.0.3 or later, and submit a bug report. Now that there are dozens of bulb and sensor models across just as many countries, sometimes there are surprises in the data that help us troubleshoot your connectivity problem. Go to the "Settings" tab inside Lightbow and submit a new "Support" ticket. (or "Send Feedback" works too—it all goes to the same person). Don't forget to flip on the switch for "Attach Diagnostics" to shed light on your Philips Bridge's actual network response.