A company hosts an application on AWS that stores files that users need to access.

A company hosts an application on AWS that stores files that users need to access. The application uses two Amazon EC2 instances. One instance is in Availability Zone A, and the second instance is in Availability Zone B. Both instances use Amazon Elastic Block Store (Amazon EBS) volumes. Users must be able to access the files at any time without delay. Users report that the two instances occasionally contain different versions of the same file. Users occasionally receive HTTP 404 errors when they try to download files. The company must address the customer issues. The company cannot make changes to the application code. Which solution will meet these requirements in the MOST operationally efficient way?