Enable AWS Session Support

Question

Honestly I'm not entirely sure what the above means. I got on with the customer support that my site template provides and they didn't seem to know what they were asking for either. I have searched the web high and low for more information to enabling this option on AWS with no luck (I'm sure some wise guy will provide a link the answers the question). Anyways below is a screenshot of where I am seeing this asked for, it is on initial site configuration. Thanks in advance!!!