Hello,
dnf update provides:
Package mozilla-openh264-2.3.0-1.fc36.x86_64.rpm is not signed
Package openh264-2.3.0-1.fc36.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