This error occurs sometimes when creating/uninstalling custom entities in drupal 8 or 9. 


The error occurs when you try to create an entity that extends:


When using one of these, you must user revisions. Thus then you need to add:

 * revision_metadata_keys = {
 *     "revision_user" = "revision_user",
 *     "revision_created" = "revision_created",
 *     "revision_log_message" = "revision_log"
 *   },

To your entity annotations. If you don't want to use revisions, you should extend


But you should know that you can't use things like workflows, because these require revisions.