Push Notifications not sending from FCM after APNs Cert change

Question

I was having no issues with sending push notifications from FCM to my iOS app before one of my certificates expired. After changing it, FCM is no longer delivering messages. I read this article (https://firebase.googleblog.com/2017/01/debugging-firebase-cloud-messaging-on.html) and here are the validation steps I've gone through so far, but am beating my head on the wall now...

• Commented out any connectToFCM functions
• Downloaded Pusher and successfully can send notifications to the device using the APNs cert
• Successfully made curl calls to FCM with success (response below)
  • {"multicast_id":7774794018682407760,"success":1,"failure":0,"canonical_ids":0,"results":[{"message_id":"0:1493321644068397%b76e8527b76e8527"}]}
• Tried recreating both development and production certs
• Tried exporting them from keychain with and without a password

Any one have experience with this super frustrating thing, and have advice on how to proceed?

It's also worth noting I'm not able to remove the APNs certs, I see the option, but it's greyed out and I can't select it.