This error is a result of an ongoing service disruption. Please follow http://status.letsencrypt.org for more information. We should have all of the remaining issues resolved shortly.
In the meantime I’m going to lock this thread since there isn’t a need for further discussion on this particular error. Please open a new thread if you need to resume discussion.
Thanks for your patience, we apologize for the disruption and I expect more detailed root cause information will be shared in the near future.