Firebase: Cannot upload production APNs certificate

Question

I am currently testing an app in TestFlight and need a production APNs certificate in order to test Notifications in Firebase.

I have followed all of the steps in th

Answer 1

Solved. The mistake I was making was that I was exporting the "private key" part of the certificate in Keychain Access instead of the "certificate" part. As soon as I re exported the .p12 using the correct row in the list - it worked.

Images to illustrate below credit iOS

Correct method: