Build fails command execution error message

`Phase context status code: COMMAND_EXECUTION_ERROR Message: Error while executing command: aws cloudformation package --template-file petstore-api.yaml --s3-bucket --s3-prefix api-code --output-template-file petstore-api-output.yaml. Reason: exit status 255
`

I received this error message after changing the placeholder for the bucket name in the main branch of my forked repo since my build was not reading the branch I created despite specifying the new branch during configuration.

I am trying to follow the tutorial to automate tests using Postman at [https://aws.amazon.com/blogs/devops/automating-your-api-testing-with-aws-codebuild-aws-codepipeline-and-postman/]; I am new to AWS.