This is part two of the series on configuring an external data type in SharePoint 2013. The first part is here.
At this point you should have already finished configuring the external data type, and created a list based on that external data type.
When you are trying to access the list you get an “Access Denied by Business Data Connectivity” error. This is caused by your configuration of your Business Data Connectivity Service. To change that you have to: