AWS CodePipeline在部署阶段失败，并出现CloudFormation错误

Question

AWS CodePipeline在部署阶段失败。这是我收到的错误：

Deployment completed, but with errors: Failed to deploy application.
Service:AmazonCloudFormation, Message:

[/Resources/AWSEBAutoScalingGroup/Metadata/AWS::CloudFormation::Init/prebuild_1_My_API/files//etc/nginx/sites-enabled/elasticbeanstalk-nginx-docker-proxy.conf] 
'null' values are not allowed in templates

我正在尝试部署到Elastic Beanstalk环境。这是我的buildspec.yml文件：

version: 0.1
phases:
  pre_build:
    commands:
      - npm install
  build:
    commands:
      - npm test
artifacts:
  files:
    - '**/*'

我正在使用aws/codebuild/standard:1.0码头工人图像。

有什么想法吗？