You have a web application with one load balancer and two servers. Sometimes a user needs to log in again during their session. What could have happened?

This issue typically arises from how session data is managed. If session data is stored locally on each server (e.g., in memory), and the load balancer doesn't use sticky sessions (or session affinity), a user's subsequent requests might be routed to a different server. This new server won't have the user's session information, forcing them to re-authenticate. To prevent this, implement a centralized session store (like Redis or a database) accessible by all servers, or configure the load balancer for sticky sessions.