Photons flashing cyan rapidly with an intermittent red flash, previously claimed and connected

[suranjan]

Thanks @ScruffR!

That made the photon connect to the cloud.
It now shows a hard fault SOS.

I can put it in safe mode and flash it, but I'd like to know what has caused this so that it doesn't recur in any of the other devices.
This particular device was working for days without a hitch, and the other photons are still running. No Red flash SOS were seen in this time.

Any ideas on what could have caused the Public Key to go bad and cause the initial cyan-red flash?
And what I could do to prevent it.

Thanks a lot!

I'm using a HTTP Client like the one in this thread,

Hard Fault with HttpClient library when using URL as hostname

I’m using the HttpClient library, https://github.com/nmattisson/HttpClient, on a Photon. I can connect to a website just fine, such as www.google.com. I have set up an API that returns JSON data on a Microsoft server and that works in the browser just fine. When I plug that URL into the hostname variable, flash the code, I get a SOS and a single blink (hard fault). The URL is formatted like this, api.xxx.xxx.net. That shouldn’t be an issue, right?