Error that makes no sense

Are you developer an iMessage app? Or trying to use one?

If you’re developing an iMessage app, you should repost over in App Frameworks > iMessage Apps and Stickers, where you’re more likely to encounter folk with experience doing that.

If you’re trying to use some other vendor’s iMessage app, I recommend that you contact that vendor for support. Alternatively, you could aske over in Apple Support Communities, run by AppleCare.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"