Not a fix but the support team suggested the following workaround which worked for me while they try and figure out what is wrong with the IOS app. I'm sure they won't mind me re-posting this here:
Would it be possible to set up your Photon using a computer instead? You'll need to have the Particle Command Line Interface (CLI) installed, so if you have not installed it yet, follow the instructions here:
if you are using Windows, make sure you use the Windows CLI Installer link and skip the other steps.
Put the Photon into Listening mode (blinking blue) by holding down SETUP until it blinks blue if it is not already blinking blue. Then issue the CLI command:
Save the Device ID; you’ll need it later.
Now enter the command:
particle serial wifi
This will allow you to configure your Wi-Fi network.
If your network uses WEP Authentication you should follow the instructions on the linked page.
Reset the Photon. The main status LED should proceed through white, blinking green, blinking cyan (light blue), fast blinking cyan, to breathing cyan. If it does not get all of the way through, include that information in your reply along with copying and pasting the command prompt output. Also, if you get any other colors after fast blinking cyan, including red or orange blinks, let me know.
Only if you get all the way to breathing cyan:
particle device add YOUR_DEVICE_ID
Now you should be fully up and running and you should be able to see your device at https://build.particle.io.