On Mon, Oct 02, 2017 at 11:50:25PM +0200, Patrick Dupre wrote: [...]
Installing: nut x86_64 2.7.4-7.fc26 fedora 1.8 M Installing dependencies: nut-client x86_64 2.7.4-14.fc26 updates 212 k Transaction Summary
FOr some reason, you have 'nut' already downloaded and it's not getting it from the cache. That doesn't match the newer version of nut-client you are trying to install, and therefore failure.
I bet "sudo dnf clean all" will clear this up.