Every week our organization clones an email and uses the newly created clone to send out a weekly alert. We do it this way so as to track analytics separately for each weeks alerts. This process has been working for a couple of years up until December 15th 2017. Since then the newly cloned email throws the following error when attempting to preview it. Additionally the email does not send. I have looked at the data object returned after posting to the REST api (when cloning the email) and the object returns success->TRUE and all result looks correct.
Anyone else seen this error? Thanks.