Error copying a page: An unexpected error occurred.

Issue

• You find an "Unexpected error occurred" message during a Copy page action.
• Checking the logs there is a trace like this:

2021-12-28 12:09:49.911 ERROR [http-nio-8080-exec-9][LayoutExceptionRequestHandler:132] User 35215 must have com.liferay.portal.kernel.model.Portlet,com_liferay_asset_publisher_web_portlet_AssetPublisherPortlet_INSTANCE_uyAYBxpmUUMw,ADD_TO_PAGE permission for null

Environment

• All Liferay Portal and DXP versions
  
  

Resolution

• The user performing the action must have the ADD TO PAGE permission for every portlet/widget in the page.
  
  
• Check your Roles configuration and be sure that the user has a Role containing these permissions, normally the User role is the default for this purpose but it could be other based on your requirements.