Event 6398 -SharePoint 2013 and 2016 comes up with some recurring issues from time to time.
The Execute method of job definition Microsoft.Office.Server.UserProfiles.UserProfileImportJob
Resolution: This just means that the Forefront Identity Manager Service is not running. Open the Services Look for the two Forefront services – you will see the Manager service is stopped:
Right click on the service and select Start – problem solved!