刚接触 Docker, Push 镜像到 docker hub 服务器总出错

[Dongdong36]

[root@localhost test]# docker images
REPOSITORY           TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
sincerefly/fedora    v2                  b751bc08ca2b        22 minutes ago      477.8 MB
sincrefly/sin-test   v1                  b751bc08ca2b        22 minutes ago      477.8 MB
sincerefly/fedora    v1                  b99a089d679e        3 hours ago         399.6 MB
sincerefly/fedora    devel               b99a089d679e        3 hours ago         399.6 MB
<none>               <none>              bec938b7a31b        4 hours ago         186.5 MB
docker.io/fedora     latest              ded7cd95e059        3 weeks ago         186.5 MB
sincerefly/fedora    latest              ded7cd95e059        3 weeks ago         186.5 MB
[root@localhost test]# docker push sincerefly/sin-test:v1

Do you really want to push to public registry? [y/n]: y
The push refers to a repository [docker.io/sincerefly/sin-test] (len: 1)
FATA[0001] Repository does not exist: docker.io/sincerefly/sin-test

我也看搜索了不少教程，看他们成功push的前边都没docker.io，这是什么情况。