解决docker认证问题 failed to authorize: failed to fetch oauth token

• 报错信息[bash1]
• 解决方案

1. 全局代理打开
2. “buildkit”: false ，见[图1]

[bash1]

>docker build -t ffpg .
[+] Building 71.8s (3/3) FINISHED                                                                  docker:desktop-linux=> [internal] load build definition from Dockerfile                                                               0.0s=> => transferring dockerfile: 23.36kB                                                                            0.0s=> WARN: FromAsCasing: 'as' and 'FROM' keywords' casing do not match (line 17)                                    0.0s=> ERROR [internal] load metadata for docker.io/library/ubuntu:20.04                                             23.5s=> [auth] library/ubuntu:pull token for registry-1.docker.io                                                      0.0s
------> [internal] load metadata for docker.io/library/ubuntu:20.04:
------1 warning found (use docker --debug to expand):- FromAsCasing: 'as' and 'FROM' keywords' casing do not match (line 17)
Dockerfile:8
--------------------6 |     #7 |     #8 | >>> FROM        ubuntu:20.04 AS base9 |10 |     WORKDIR     /tmp/workdir
--------------------
ERROR: failed to solve: ubuntu:20.04: failed to resolve source metadata for docker.io/library/ubuntu:20.04: failed to authorize: failed to fetch oauth token: Post "https://auth.docker.io/token": dial tcp 69.63.176.15:443: connectex: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

[图1]