The system status is showing the issue was resolved perhaps an hour ago, but I'm still waiting for a response and an xcrun query is showing "in progress".This kind of delay or outage is unacceptable.

Thank you very much, I shall have a crack at things after reading through the contents of your link.

Thanks again, that did the trick, and I've noted that link for future reference if needed again.

Chiming in to say the same thing has been happening for me right now, and also over the last few days. Having other code-signing problems ('unnotarized Developer ID' reported by spctl) that didn't arise previously, but am assuming this is a coincidence.

Also chiming in to say I am having the same issue running the same command line as 'billfromlos gatos', and can't find any information other than this thread.