dnf Upgrade Produces GPG Error

[Stephen Morris]

Hi,

I've just attempted to do a sudo dnf upgrade to install the 343 
updates that are available, and after downloading all the packages it 
got a GPG error and terminated. Has anyone else seen this and is able to 
provide some guidance on what I need to look at to identify why?

[SKIPPED] vulkan-filesystem-1.1.70.0-1.fc27.noarch.rpm: Already downloaded
[SKIPPED] xdg-utils-1.1.2-4.fc27.noarch.rpm: Already downloaded
[SKIPPED] xfsprogs-4.15.1-1.fc27.x86_64.rpm: Already downloaded
Package flash-plugin-29.0.0.113-1.fc27.x86_64.rpm is not signed
The downloaded packages were saved in cache until the next successful 
transaction.
You can remove cached packages by executing 'dnf clean packages'.
Error: GPG check FAILED

regards,

Steve