AWSCodeBuild, Status Error 400

You might be hitting the service limits for CodeBuild. See https://docs.aws.amazon.com/codebuild/latest/userguide/limits.html. If so, please raise request to increase the service limits. If it's not due to service limits (e.g. this is the first time you are trying to use CodeBuild and still seeing this error) then please contact AWS Support and raise a ticket so they can help.