Using the iOS app, I tried to connect my photon to WiFi. I went through the whole setup and the app was able verify ownership of the device.
The problem is that the photon is now fast flashing cyan (with some green flashes now and then) and the app says that the device is offline.
What does this mean?
I had a similar problem and just found the solution. In a test I was running I selected to use a static IP. It turns out that setting is retained so even after reclaiming my photon and reinstalling tinker, it was still trying to use the static IP. Once I downloaded a new program and selected a dynamic IP, I still had to reclaim the device using the iPhone app, but It connected right away and has worked fine since.
That's correct. The docs for WiFi.useStaticIP() say
The setting is persistent and is remembered until WiFi.useDynamicIP() is called.
This so the device can still connect to the WIFi network when in safe mode.