How to resolve 'Verification codes can’t be sent to this phone number' error during Apple Account sign up?

I just had this issue, and went through chat and phone support who couldn't figure it out (though they were very polite).

The dumb fix is:

1. Create an icloud.com account first for the email being invited to the Apple Developer Program.
2. Then click "Accept invitation" in the invite email.

The real fix is:

Your new account password MUST have a special character in it... BUT the flow for account creation from the Accept Invite email does not verify you've done that.

Thus, something on the backend is validating the password sent at the time it wants to send an SMS code.. and failing, but not passing back the error info.. so the response is just a generic "something is wrong with this number"

The general icloud.com account creation flow WILL remind you to use a special character.

It suddenly started working with my google voice number. Try it quick! Before it goes down again!

(and maybe try a us google voice number?)

The plot thickens!

I saw you posted today and since I'm trying to create a work account today, figured it was a service issue.

Maybe it's something else, then. But a bug in their validation or otherwise a service issue makes the most sense to me.

I'm guessing the service is down. I'm having the same issue with both my google voice number which already works on another account. It also failed to work on my normal cell phone number.