com.apple.AuthenticationServices.Authorization Error Code 1000

Turns out to be problems with missing settings in csproj.

Found the Answer here: https://xamarin.github.io/bugzilla-archives/25/25141/bug.html

I opened csproj and discovered some build configuration were missing CodesignEntitlements and some of them were empty:

<CodesignEntitlements>Entitlements.plist</CodesignEntitlements>

After adding it to/updating it in all build configurations it finally works.

PS: Before that I tried to create empty xamarin project (with the same bundle name) and it reproduced the problem on simulator. Then I did swift project (with the same bundle name) and it worked fine. So it was clear that it was xamarin specific bug.

Fist of all, all above answer are correct to me.

Second, I spend some hours to found out that I miss add Sign with Apple ID Entitlements in release config, So I just past what I do here.

You can check by any one of bellow:

1. Check every tab under Signing & capabilities in Xcode

2. Search com.apple.developer.applesignin in vscode(or other file tool), you should find 3 Entitlements files

3. Check files in project folder in vscode(or other file tool), you should find 3 Entitlements files with com.apple.developer.applesignin included.

I got this error because forget to add sign in capability.

After searching I found that it works on a real device and SOMETIMES doesn’t work on the simulator.

But I solved it by logging in here and removing the simulator under Devices. Then building it again. Don't forget to add “Sign in with Apple” in “Signing & Capabilities”.