Description of problem: Used 32-bit Fedora 29 network install to install basic system to USB memory stick. Logon and su - dnf update Get above error message.
Could you provide more details on what has happened? Logs and additional debug info would be nice. It's not clear whether it's a problem with dnf or infrastructure (unavailable mirror etc.)
I gave up trying to use the minimal install system. Most likely a user error. It has been replaced by the basic desktop install.