AWS codebuild 失败，并显示错误：- COMMAND_EXECUTION_ERROR：执行命令时出错：yarn run build。原因：退出状态1

Question

我正在尝试使用 aws codebuild 来创建 ci/cd 管道。我使用纱线作为包管理器。这是我的构建规范文件。

# Do not change version. This is the version of aws buildspec, not the version of your buldspec file.
  version: 0.2
  phases:
    install:
      commands:
            - echo update npm...
            - npm install -g n
            - n latest
            - npm update -g npm
            - echo node -v
            - node -v
            - echo npm -v
            - npm -v
            - echo install yarn...
            - npm install -g yarn
            - echo yarn -v
            - yarn -v
    pre_build:
      commands:
        #installs dependencies into the node_modules/ directory
        - echo Entered the pre_build phase...
        - yarn install
    build:
      commands:
        - echo Build started on `date`
        - echo Compiling
        - yarn run build
    post_build:
      commands:
        - echo Build completed on `date`
  # Include only the files required for your application to run.
  artifacts:
    files:
      - public/**/*
      - src/**/*
      - package.json
      - appspec.yml
      - scripts/**/*

PS：由于某种原因，仅编写纱线在预构建阶段不起作用。但现在它在构建阶段显示错误。

COMMAND_EXECUTION_ERROR: Error while executing command: yarn run build. Reason: exit 
 status 1

由于我是 AWS 新手，我无法找到解决方案。如果可能的话，请帮助我。 谢谢