Sometimes when a user updates or Activates an Adobe Target Activity, they get an "Activity Sync Error" which means the activity doesn't sync with the Target back end, so they'll never actually be served up on a client site.There isn't any particular activity setting or configuration due to which sync errors are triggered.Typically, it could be that the activity/audience is in a bad state (could be corrupted, too big, incompatible).
However, there are some common causes of synchronization errors derived from the past use-cases. For more info see: https://helpx.adobe.com/target/kb/troubleshooting_activity_sync_error.html
