Docker for Windows Container Update Problem

Installing a Linux container and trying to update the repos end with “service unavailable”

>      [email protected]:/var/www/html# apt-get update
>     Ign:1 http://security.debian.org/debian-security stretch/updates InRelease
>     Ign:2 http://deb.debian.org/debian stretch InRelease
>     .
>     .
>     .
>     E: Failed to fetch http://deb.debian.org/debian/dists/stretch-updates/main/binary-amd64/Packages
> 503  Service Unavailable [IP: 149.20.4.15 80]
>     E: Failed to fetch http://deb.debian.org/debian/dists/buster/main/binary-amd64/Packages 
> 503  Service Unavailable [IP: 149.20.4.15 80]
>     E: Failed to fetch http://deb.debian.org/debian/dists/buster-updates/main/binary-amd64/Packages
> 503  Service Unavailable [IP: 149.20.4.15 80]

The Host (Windows 10) runs with activated firewall defender, the log shows:

   2019-07-12 08:04:08 ALLOW TCP myIP*** 149.20.4.15 55367 80 0 - 0 0 0 - - - SEND
2019-07-12 08:04:08 ALLOW TCP myIP*** 149.20.4.15 55370 80 0 - 0 0 0 - - - SEND

So I can send but not receive, it seems. Isn’t it?

Source: StackOverflow