Breaking story here:
On Sep 12th, an Alaskan Airlines flight had a failure of their CMU (Comms Management Unit) that caused the Iridium connection to stop working. An ATC message was sent to the aircraft but not delivered. On the next flight, the CMU power was reset and corrected the issue, and the pending message was delivered. The CMU did not recognise the message as being old, and so it was presented to the Flight Crew as a control instruction. FSB understands that this aircraft took the climb instruction and executed the level change, climbing 1000 feet.
Right now, Auckland (NZZO), Anchorage (PAZA), and Oakland (KZAK) Oceanic have told operators not to use Iridium for CPDLC, and FSB expects more to follow, including New York Oceanic later today. If the timeline to fix the issue is correct, then a worldwide ban on Iridium for CPDLC seems very likely.
Iridium fault prompts ban by Oceanic ATC ? International Ops 2017