when your web browser or android device browser makes a TCP connection to an elastic load balancer, the connection is used for request and response. it remains open for a short amount of time like 60 seconds. behind the scenes, elastic load balancing and it is set for 60 seconds. and when you have a big file to read from a database like a report then it will be timeout after 6o seconds .
approximately 60 seconds is enough but when the file read-write computation is more like fetching big application banking report statements or centralized ERP solution fetching all the student reports .so it might be 60 seconds is not enough for fetching from database.
in some circumstances, different idle timeout values are more appropriate. Some applications can benefit from a longer timeout.you can now set the idle timeout for each of your Elastic Load Balancers to any desired value between 1 and 3600 seconds (the default will remain at 60).