RDP Cannot Connect

Hello, Few things to go over here: As commented previously, if you can confirm both the Security Group(s) allow inbound traffic from your location to port 3389? You can further test using PowerShell: PS C:\ > tnc <ip_address> -port 3389

If you can reach it, let us know if the Instance is passing both System Checks in the Console, System for AWS underlying host and Instance for OS. If it's failing the first, stop and start the Instance so it lands in a new host, if it is the second, then this is related to the OS.

Keep in mind to get a backup of the Instance in the form of AMI or Snapshot before continuing.

Check the Screenshot of the Instance to validate there is no issue in the network card (we want to avoid yellow or red icons). If the Instance is managed by SSM, try running SSM Automation and discard these culprits to help troubleshooting.

Lastly you can also use Ec2Rescue to see if something was modified in terms of Firewall or settings for Remote Desktop.

Reach out to your Sys Admin to also validate no GPOs are cascading to the Instance which may be meddling with connectivity, also sometimes 3rd party software like Antivirus or Firewall could be in the way of connecting.

I hope the information above is helpful.