Blinking up aria not working

I’m trying to blink up a few arias. I’ve tried two different boards, with 3v and 5v power. I’m blinking up with an iPhone running iOS 7.1.1
It just keeps blinking red on and off. According to the blink up troubleshooting guide, this means it’s not accepting the blink up.
What should I do?

Here’s a video you can use to double-check your procedure:

If it’s still not working, can you see whether the LED turns off at the start of BlinkUp and stays off until it has finished?

Are the red LED blinks equally spaced? If not you could try re-entering your SSID and password, and confirm that the network is 2.4GHz (not 5GHz).

What are you using to power the board? If the Imp isn’t getting enough current, it will just boot loop over and over.