I did everything as you suggested, and still got same error:
In the following image you can see .config file was created with the proper permission in the document root folder, in this case, for Laravel + Elastic Beanstalk, that folder is: /var/app/current/public
https://s3.amazonaws.com/swyftfilings-resources/Screen+Shot+2018-11-04+at+10.45.03+AM.png