fai-make-nfsroot fails to download certain packages

Hello,

*MY ENVIRONMENT:*

*uname -a*
Linux pubwww3 4.9.0-4-amd64 #1 SMP Debian 4.9.51-1 (2017-09-28) x86_64 
GNU/Linux

*cat /etc/debian_version*
9.2

*dpkg -l | grep fai*
ii  fai-client 5.3.6                             all          Fully 
Automatic Installation client package
ii  fai-doc 5.3.6                             all          Documentation 
for FAI
ii  fai-server 5.3.6                             all          Fully 
Automatic Installation server package

*cat /etc/apt/sources.list*
deb http://ftp.uk.debian.org/debian stretch main contrib non-free
deb-src http://ftp.uk.debian.org/debian stretch main contrib non-free

deb http://security.debian.org/ stretch/updates main contrib non-free
deb-src http://security.debian.org/ stretch/updates main contrib non-free

# For MegaRAID SAS utilities
deb http://hwraid.le-vert.net/debian stretch main

*apt update*
Hit:1 http://security.debian.org stretch/updates InRelease
Ign:2 http://ftp.uk.debian.org/debian stretch InRelease
Ign:3 http://hwraid.le-vert.net/debian stretch InRelease
Hit:4 http://ftp.uk.debian.org/debian stretch Release
Hit:5 http://hwraid.le-vert.net/debian stretch Release
Reading package lists... Done
Building dependency tree
Reading state information... Done
381 packages can be upgraded. Run 'apt list --upgradable' to see them.

*/usr/share/apt-cacher/apt-cacher-import.pl -l /var/cache/apt/archives*
Importing from /var/cache/apt/archives
Symlinking package files from /var/cache/apt/archives to 
/var/cache/apt-cacher
/var/cache/apt-cacher/headers/acl_2.2.52-2_amd64.deb already exists: 
skipping
(...)
Done.
0 files imported

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*MY ERRORS:
*
*fai-make-nfsroot -v -f*
Using configuration files from /etc/fai
Creating FAI nfsroot in /srv/fai/nfsroot
Creating base system using debootstrap version 1.0.89
Calling debootstrap --exclude=info --include=aptitude stretch 
/srv/fai/nfsroot http://localhost:3142/debian
I: Retrieving InRelease
I: Retrieving Release
I: Retrieving Release.gpg
I: Checking Release signature
I: Valid Release signature (key id 067E3C456BAE240ACEE88F6FEF0F382A1A7B6500)
I: Retrieving Packages
I: Validating Packages
I: Resolving dependencies of required packages...
I: Resolving dependencies of base packages...
I: Found additional required dependencies: libaudit-common libaudit1 
libbz2-1.0 libcap-ng0 libdb5.3 libdebconfclient0 libgcrypt20 
libgpg-error0 liblz4-1 libncursesw5 libsemanage-common libsemanage1 
libsystemd0 libudev1 libustr-1.0-1
I: Found additional base dependencies: aptitude-common dmsetup 
gnupg-agent libapparmor1 libassuan0 libboost-filesystem1.62.0 
libboost-iostreams1.62.0 libboost-system1.62.0 libbsd0 libcap2 
libcryptsetup4 libcwidget3v5 libdevmapper1.02.1 libdns-export162 libelf1 
libfastjson4 libffi6 libgmp10 libgnutls30 libhogweed4 libidn11 libidn2-0 
libip4tc0 libip6tc0 libiptc0 libisc-export160 libksba8 
liblocale-gettext-perl liblognorm5 libmnl0 libncurses5 
libnetfilter-conntrack3 libnettle6 libnfnetlink0 libnpth0 libp11-kit0 
libpsl5 libseccomp2 libsigc++-2.0-0v5 libsqlite3-0 libtasn1-6 
libtext-charwidth-perl libtext-iconv-perl libtext-wrapi18n-perl 
libunistring0 libxtables12 pinentry-curses xxd
I: Checking component main on http://localhost:3142/debian...
I: Retrieving libacl1 2.2.52-3+b1
W: Couldn't download package libacl1 (ver 2.2.52-3+b1 arch amd64)
I: Retrieving adduser 3.115
W: Couldn't download package adduser (ver 3.115 arch all)
I: Retrieving libapparmor1 2.11.0-3+deb9u2
I: Validating libapparmor1 2.11.0-3+deb9u2
I: Retrieving apt 1.4.10
I: Validating apt 1.4.10
(...)
E: Couldn't download packages: libacl1 adduser aptitude aptitude-common 
base-passwd bash libboost-filesystem1.62.0 libboost-iostreams1.62.0 
libboost-system1.62.0 bsdmainutils libbz2-1.0 libdebconfclient0 
coreutils cpio libcwidget3v5 dash libdb5.3 debconf debconf-i18n 
debianutils dmidecode libelf1 findutils libgdbm3 grep gzip hostname 
ifupdown init init-system-helpers iptables libip4tc0 libip6tc0 libiptc0 
libxtables12 kmod libkmod2 libassuan0 libbsd0 libcap-ng0 libestr0 
libfastjson4 libffi6 libgpg-error0 libidn2-0 libksba8 
liblocale-gettext-perl liblogging-stdlog0 liblognorm5 libmnl0 
libnetfilter-conntrack3 libnfnetlink0 libpipeline1 libpsl5 libselinux1 
libsemanage-common libsemanage1 libsepol1 libsigc++-2.0-0v5 
libtext-charwidth-perl libtext-iconv-perl libtext-wrapi18n-perl 
libunistring0 logrotate lsb-base liblz4-1 mawk nano netbase libhogweed4 
libnettle6 libnewt0.52 whiptail libnpth0 libp11-kit0 libpam-modules 
libpam-modules-bin libpam-runtime libpam0g libpopt0 libreadline7 
readline-common rsyslog sed libslang2 sysvinit-utils tar tasksel 
tasksel-data libustr-1.0-1 liblzma5
Log file written to /var/log/fai/fai-make-nfsroot.log

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Has it got anything to do with my FAI master distro being behind (9.2 < 
9.13)?

I don't care much if my FAI client nodes will run 9.2 or 9.13.

Can you explain why only some packages fail to download and how to fix it?

Regards,
Adam