Fix “Unable to render the data. If the problem persists, contact your web server administrator.” Issue in SharePoint BCS

Problem:
Tried created an external list SharePoint 2016 using business data connectivity services, configured secure store target application, and created an external list in SharePoint. All went well; however, the external list displayed this error message with a correlation ID.
Unable to render the data. If the problem persists, contact your web server administrator.

I ran ULS Log viewer and found this message in the logs:
Error while executing web part: Microsoft.BusinessData.Infrastructure.BdcException: The shim execution failed unexpectedly – Unable to obtain the application proxy for the context.. —> Microsoft.Office.SecureStoreService.Server.SecureStoreServiceException: Unable to obtain the application proxy for the context.   

Solution:

The root cause of the problem is: The web application is not associated with the secure store service application. So, the solution is:

• Go to SharePoint 2013/2016 Central Administration site
• Application management >> Click on Configure service application associations under Service Applications.
• Pick the web application in which your site exists, check the “Application proxy group” column >> Make sure the BDC and secure store service applications check boxes checked.