cups-2.2.2-7.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2017-85a204e9b9

cups-2.2.2-7.fc26 has been pushed to the Fedora 26 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-85a204e9b9

cups-2.2.2-7.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report.

If we place an NIS group name in the SystemGroup parameter in
/etc/cups/cups-files.conf then CUPS will not start correctly at boot
time and gives an error message saying there's a bad group.

Reproducer usable for RHEL 7/CentOS 7 (packages may differ for Fedora):

1. machine - <server hostname> - NIS server
a) $ yum install ypserv ypbind portmap yp-tools
b) edit /etc/sysconfig/network:
   
   NISDOMAIN=<DOMAIN.COM>

c) $ ypdomainname <DOMAIN>COM
d) add into /etc/yp.conf:

   ypserver 127.0.0.1

e) $ systemctl restart ypserv, yppasswdd
f) edit /var/yp/Makefile:

   MERGE_PASSWD=false
   all:  passwd group hosts rpc services netid protocols mail shadow

g) $ /usr/lib64/yp/ypinit -m
h) $ authconfig --update --nisdomain=<DOMAIN.COM> --nisserver=<server hostname> --enablenis
i) $ systemctl restart ypbind, ypxfrd, yppasswdd
j) $ groupadd nis-group
k) $ useradd -g nis-group nisuser
l) $ passwd nisuser
m) $ make -C /var/yp

2. machine - <client hostname> - NIS client and CUPS server
a) $ yum install -y ypbind yp-tools
   $ sudo systemctl enable ypbind
b) $ nisdomainname <DOMAIN.COM>
c) edit /etc/sysconfig/network

   NISDOMAIN = <DOMAIN.COM>

d) edit /etc/yp.conf

   domain <DOMAIN.COM> server <server hostname>

e) edit /etc/nsswitch.conf

   passwd:     files nis        [ add "nis" service ]
   shadow:     files nis        [ add "nis" service ]       
   group:      files nis        [ add "nis" service ]

f) $ authconfig --update --nisdomain=<DOMAIN.COM> --nisserver=<server hostname> --enablenis
g) $ yum install -y cups
h) edit /etc/cups/cups-files.conf

   SystemGroup sys root nis-group

i) $ reboot
j) $ systemctl status cups