Here are the complete steps to initialise Apple authentication that I've followed, but I can't seem to find a solution to this issue. Add your personal email accounts so you can read and send email on your device. However, I've tried that, and it returned undefined, as shown below. This is required for so much of your contact with Apple and it’s software. Fortunately, as log as you can still log into your Apple ID account at, you. I saw a solution in the thread - to get the updated credential key from the error message returned by calling erInfo, and use it to link the Apple account with another account on Firebase. You’re not going to get started, with Apple, without first registering an email address as your Apple ID. Apple lets you change your Apple ID address without having access to the original email within iOS. I understand that reusing credentials to link accounts is not allowed for Apple, and someone has mentioned this issue as well. However, when I try to do the same with Apple accounts (link Apple account with phone number), it's returning this error: Duplicate credential received. To set up an icloud email address confirm the process by selecting the Create Email Address button.
Select Get a free iCloud email address Now, enter the username which you want to use in your iCloud account.
I've managed to authenticate and link Google accounts to phone numbers on Firebase using linkWithCredential. Now, enter your Birthday, First Name and Last Name.
I'm developing an application using React Native, and authenticating users on Firebase.