Sometimes, you’ll receive a Stax client ID mismatch error when you’re trying to link Stax to your AWS account.
This happens if you change the Stax Client ID you entered into the Stax-provided External ID space on the AWS Create Stack page.
To fix it, go to the Stax account linking process and click the Open AWS Console button again.
This will open the AWS console Create Stack page with the CloudFormation template attached again. This time, make sure you leave the external ID exactly as it appears when the page loads.