I'd suggest a few things to try -
1. If you have enabled entity permissions on this entity list then check that you have actually created entity permission for that entity, provided write and delete privileges. Also ensure that you have associated this entity permission with the web role of your logged in user.
2. Once your entity list configuration is saved, from portal studio / editor click 'Browse Website' to ensure that the cache is cleared and updated configuration for entity list is picked by the portal application.