In the event that the timestamp server cannot be reached for whatever reason, codesign simply fails. This is probably a good idea, because if it’s important for signed code to also contain a timestamp, you wouldn’t want to accidentally ship a major release of your app without it. But because the timestamp server can be unavailable for a variety of reasons, some of them common, we need some simple solution for continuing with the the day-to-day building of our apps without ever being bothered by the pesky timestamp service issue.
Lucky for us, such a solution exists in the form of a codesign command-line flag: “–timestamp”. Ordinarily this flag is used to specify the URL of a timestamp server, if you choose to use one other than the Apple default. But a special value none indicates that timestamping of the signed code should be disabled altogether.
It’s not clear to me why the timestamp servers should be so unreliable.