When doing a pre-migration check or copying a site object, the following message is displayed:
No managed metadata service is set as the default service for Enterprise Keywords. This field cannot be copied.
This issue can happen when migrating the Enterprise Keywords column if the destination has no managed metadata service set as the default service for Enterprise Keywords.
Make sure that Enterprise Keywords are properly set-up at your destination. To easily do this, you can simply add the Enterprise Keywords column to a list and SharePoint should normally configure it for you.