Fix AWS RDP Connection Error

My Windows-based EC2 instance suddenly refuses Remote Desktop connections. Each time I try to log in I get a “too many attempts” style message, then the session closes. Rebooting from the AWS console and resetting the RDP listening port haven’t helped, so I need someone who knows the ins and outs of AWS networking, IAM permissions and Windows Server recovery modes to bring the instance back online via RDP.

What I’ve confirmed so far
• The security group still allows port 3389 from my IP.
• The instance status checks show “2/2 passed.”
• Password and key pair are unchanged, so the issue appears to be connection-level rather than credentials.

Your task is to diagnose the root cause—whether it’s network throttling, NLA mis-config, mis-cached credentials, or something deeper—and restore reliable RDP access. Please be comfortable with SSM Session Manager, EC2 Rescue, and standard Windows Server troubleshooting tools so we avoid unnecessary downtime.

Deliverable: a working Remote Desktop session and a short note summarising the fix applied, so I can replicate it if the problem recurs.