Access denied when accessing external lookup

Hello. I have a problem concerning external data.

I have a list with an external data column, connected via SharePoint Designer 2013 to an SQL view. Being the SharePoint administrator, I can personally access all the data, while every other user simply get an "Access denied." and cannot even see any elements containing external data.

For testing purposes, I've made another user Owner of the site and given her full permissions in the BCS section of the SharePoint Administration. And still she cannot access the external view.

This is presumably a permissions issue, so any ideas to what other boxes need to be checked? :)

Thanks in advance.