@ambesh
Did this email action exist in this workflow prior to July 1 and did you modify this action in the existing workflow? We released an updated version of the “Send Email” action as of 07/01 that supports non-id tied recipient lists. If you are putting in manual recipients that are not tied to IDs that may be the issue. In order to not break existing workflows, the old actions will remain in the existing builder. If, however, you want to take advantage of features in the new action (like non-id related recipients) you would need to drag in the new action into the builder and configure that new action.