Fix Login Loop After AWS

Our customer-facing login portal suddenly stopped working right after a previous freelancer performed AWS cost-optimization tasks (Reserved Instances, auto-scaling tweaks, and some security-group changes). Users enter their credentials, hit “Sign In,” and are immediately bounced back to the login screen with no specific error—so sessions clearly aren’t being established or persisted.

Here’s what I need from you:
• Diagnose the exact cause of the loop (session handling, load balancer stickiness, Cognito/IAM policy, or any other AWS-related misconfiguration).
• Restore normal authentication flow so clients can reach their dashboards again.
• Provide a concise technical summary of the root issue and the steps you took, so we can avoid a repeat.

Stack details you’ll touch: AWS EC2 (Ubuntu), Application Load Balancer, RDS (MySQL), Redis cache, Nginx reverse proxy, and a Laravel back-end. You’ll get SSH and AWS Console access in a dedicated IAM role; please keep changes version-controlled and document anything you modify.

Acceptance criteria: successful login on both desktop and mobile browsers, sessions persist for the configured timeout, and no collateral regressions.

If you’ve untangled authentication problems after AWS infrastructure changes before, this should be straightforward. Let me know your typical turnaround time and any information you need up front; I’m ready to move quickly.