Did you ever find a solution for this? I am having the exact same problem all of sudden (began this week) on my Jenkins build server.

Thank you for the response and clarification. Oddly enough, the builds from today began working again, so potentially it is an intermittent issue, somewhere ... either on my server, with the Cloudkit server, or something in between. In any case, this gives me a much better idea of where to go hunting next time this happens. Cheers! - Rob / MOK

I am suddenly getting this now, and can't find any reason for it. Checked my account, Team ID and account status is all good.