Article missing import ID
When you first start using the API method you may find that some articles report back with This article does not have an import ID. This is normally because the article hasn't been synced using the API method before, to fix it simply update the post in WordPress to force an API sync.
In some case this might not fix it entirely. Occasionally this can be caused by using the background CRON method to sync your posts. To disable it go to the API tab in the WP Native Articles admin menu and untick the CRON Sync method and save. Then try re-updating your post as described above.