Hi all,
please do not install nut-2.8.0 upgrade from EPEL, it includes a lot of breaking changes which will not be suported. IT was for the last few days in our repos too, but it has been removed for this reason.
if you did install it, to fix the issue
yum downgrade nut nut-client
systemctl restart nut
If you also have nut-cgi on your server you might also need to first rmeove it, downgrade and then reintall it from EPEL archive.
rpm -e nut-cgi
yum downgrade nut nut-client
systemctl restart nut
wget https://archives.fedoraproject.org/pub/archive/epel/7/x86_64/Packages/n/nut-cgi-2.7.2-4.el7.x86_64.rpm
yum install nut-cgi-2.7.2-4.el7.x86_64.rpm
also please if EPEL is enabled by default on your server, exclude nut and nut-client
db yum_repositories setprop epel Exclude perl-Razor-Agent,pwauth,nut-client,nut
signal-event yum-modify