Access denied by business data connectivity in SharePoint 2013

Problem:

In SharePoint 2013, when I tried to access the external list I was getting the following error.

This is because the user doesn't have the permission to the external content type.

How to resolve:

1. Open Central Administration.
2. Click on Manage service applications which is available in the Service Applications section.
3. Click on BCS service application.
4. Select the external content type, click on Set Permissions in the ECB menu.