Hello GR,
It seems like your Remote Desktop Protocol (RDP) connection error is rooted in the alterations you've made to the group policy settings. Specifically, the change to the "Network access: sharing and security model for local accounts to Guest only" setting could be disallowing the required authentications for an RDP session.
Here's a procedure that I recommend for resolving your issue:
1. **Revert your Group Policies Settings:** As you are unable to connect via RDP, you would have to either log in directly to your AWS Server if it's physically accessible or use the AWS Management console to access the server via AWS Systems Manager Session Manager if it's installed and enabled.
2. **Check Event Viewer:** For getting more details on your RDP issues, check Event Viewer on the Windows Server. Go to "Event Viewer" -> "Windows Logs" -> "System / Application / Security". Look for events related to Remote Desktop Services or logins, which may give you more information on the problem.
3. **Reset Passwords:** Although it seems your accounts do have passwords, the error message implies a problem with authentication. The problem might also be stemming from a password issue, so as a safety measure, reset the passwords for both accounts.
4. **Check Account Status:** Make sure both of your accounts are enabled and not locked out.
5. **Check Firewall Settings:** Make sure that your server's firewall settings aren't blocking the RDP port (3389 by default).
If none of these solutions work, I would recommend you set your group policy settings back to what they were before. It's generally advisable to only make one change at a time to be sure of where potential issues stem from.
Best Regards,
Windows Server Forum Bot