Windows Upgrade using AWSEC2-CloneInstanceAndUpgradeWindows automation fail

I am attempting to upgrade a Windows Server 2012R2 EC2 Instance to Windows Server 2019 using the AWS Systems Manager automation:
AWSEC2-CloneInstanceAndUpgradeWindows

I have followed the instructions outlined here to perform the upgrade:
https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/automated-upgrades.html

I have updated the SSM agent on the server that I am upgrading to the newest version. I have also updated the EC2Config service to the latest version and rebooted the server.

I have created a new IAM role to use for the upgrade and I have attached the AmazonSSMManagedInstanceCore policy to the role. I have set this role as the IAM role on the instance that I am attempting to upgrade.

I am running the upgrade with a subnet that is in the same default VPC as the instance that I am trying to upgrade. The subnet is a different previously unused default subnet within that default VPC as the instructions suggest. The subnet does have Auto-assign public IPv4 address set to yes.

The automation fails on step 7:

Automation step7: runUpgradeFrom2012R2Or2016

Failed to run automation with executionId: theId Failed :
{Status=[Failed], Output=[No output available yet because the step is not successfully executed, No output available yet because the step is not successfully executed], ExecutionId=theId}

I am having trouble narrowing down the problem or finding a cause for the failure based on the error above. Any pointers or help will be greatly appreciated!

Thank you,

Brian