Cannot connect using RDP because of invalid password

https://lightsail.aws.amazon.com/ls/docs/en_us/articles/use-non-default-key-with-windows-based-instance-in-lightsail I tried to change Administrator password using Windows Server by decrypting the key. So I tried to get the ciphertext using the AWS CLI aws lightsail get-instance-access-details --instance-name my-instance and got output as follow.

{
    "accessDetails": {
        "ipAddress": "my_ipaddress",
        "password": "",
        "passwordData": {
            "ciphertext": "",
            "keyPairName": "LightsailDefaultKeyPair"
        },
        "protocol": "rdp",
        "instanceName": "my_instance_name",
        "username": "Administrator",
        ........
    }
}

You can see the ciphertext is empty. So, I cannot decrypt the password from the ciphertext. Please kindly help us asap.

Hi There

If you used the Default Key and did not change the windows password from within windows, you should be able to RDP using the Windows RDC client from your desktop and connect directly to the public IP address using the original password. If that doesn't work, then the password was likely changed within windows and you wont be able to recover it. Is it possible that someone else changed the password?