Devices can't connect to internet, blinking cyan, green and yellow

[ScruffR]

There has been another report of such an issue not too long ago, have a look here

All Spark Cores can't connect to the cloud

This could be due to some issues with DNS resolution on the Cores after a server switch. Try running these commands after clearing the WiFi credentials and putting your device in DFU Mode particle flash --usb cc3000 particle flash --usb tinker particle keys server particle keys doctor <youDeviceID> And then in Listening Mode reapply the WiFi credentials particle serial wifi