I've been developing an app using Firebase and it's Firebase messaging service for push notifications. I've had push notifications working perfectly for the past month or so, until today. I uploaded my app build onto testflight maybe ~4 days ago and have since still been making changes locally. Yesterday push notifications started acting weird with my just latest firebase token giving an error, and then today there are no errors, the notifications simply don't show up.
I decided to try debugging by sending a push notification straight through terminal and through an app I found "Pusher", but I've used before (without any problems) to send push notifications using my devices token. I got the latest token, and tested it manually through terminal and through the app, and both sent sucessfully but were not received. Thus, it seems the problem is somewhere between the apple servers and my app.
I then decided to checkout to the testflight commit, and the push notifications still weren't working in development. However, when I tested the app on testflight, push notifications did work. I'm incredibly confused, as this seems to imply it isn't an issue with my app or any changes I've made in the past few days (which makes sense as none of them really had anything to do with push notifications). I have two separate certificates, a development and a production for APNS which have expiration dates late in 2018.
If anyone has any insight into why notifications would suddenly stop working in development (while they are still working in production with no code differences between development and production) it would be greatly appreciated.