不存在或没有拉取访问权限（Docker compose）

我想对我的spring boot/spring云应用程序进行dockerize

docker compose.yml:

eureka:
  build: ./eureka-discovery-service
  ports:
    - "8761:8761"

mongodb:
  image: mongo:3.0.4
  ports:
    - "32768:32768"

postgresql:
  image: postgresql:9.6-2
  ports:
    - "5432:5432"

gateway-service:
  build: ./gateway-service
  ports:
    - "9090:9090"
  links:
    - eureka

airplane-service:
  build: ./airplane-service
  ports:
    - "2222:2222"
  links:
    - eureka
    - postgresql

car-service:
  build: ./car-service
  ports:
    - "2220:2220"
  links:
    - eureka
    - mongodb

machine-service:
  build: ./machine-service
  ports:
    - "2224:2224"
  links:
    - eureka

我在进行docker撰写时收到以下错误消息：

---

如何解决这个问题以及我为什么会遇到这个问题？

图像名称应该是

postgres:9.6.4

图像名称应该是

postgres:9.6.4

Pulling postgresql (postgresql:9.6-2)...
ERROR: repository postgresql not found: does not exist or no pull access