This is what seems to have "fixed" it, although Im really not sure what the real cause was. I re-made a new APNS key. I made sure the users affected reboot their phones (I saw that hint on something I was looking at). After a few days things started working again. I still dont know why all devices stopped working in December out of the blue. Thank you for the tips and advice. Appreciate it.

Also sending the device token that my device registers with Apple (via the Apple test notifications page) tells me that the device token is invalid yet when I send it to api.development.push.apple.com it returns status 200. Im not sure why Im seeing so many inconsistencies since December.

It turns out that only one of the devices was offline (The notifications were turned off) but it appeared to report multiple devices the same way. After that, I also noticed after I created that new APNS Key (for Sandbox & Production) I was still getting fails when sending to https: api.sandbox.push.apple.com api.push.apple.com But when I send them to: api.development.push.apple.com They appear to work correctly. I have no idea what first caused the issue and it also seems like I have some other issues still occuring. alert background Some alert types work some dont. some background types work, some dont. Very odd. Im still trying to figure out why things changed outside my control. And yes Ive been using HTTP/2 for a while now.