Some servers in our Arizona Data centre are having difficulties in getting new LetsEncrypt SSL Certificates added to their account, this will also affect renewals on some domains. We are looking in to this issue and we will provide more information as it becomes available.
As of 12PM EDT 10/27/2019 :: We have been monitoring this issue and we now deem this to have been resolved, all certificates that did not issue yesterday are now in place. Please let us know if you still see issues in a ticket.