Buildx issues

[+] Building 3.4s (2/3)                                                                                                                                                        docker:default
 => [internal] load build definition from Dockerfile                                                                                                                                      => [internal] load metadata for docker.io/library/python:3.9-alpine                                                                                                                     3.3s

There is not IP traffic to docker.io host!

Reason: registry mirror was set in /etc/docker/daemon.json, but access to this registry was blocked on FW.