Temporary name resolution failure

I am running Ubuntu 21.10 on a laptop computer. Clean install worked fine. ran apt-get update && apt_get upgrade. Now network is all "temporary failure in name resolution'. Every other computer on the home network is fine. This looks like 'fail by default' to me, but 30 years into linux that seems unlikely. What do i need to check?
/etc/host and /etc/hostname match.
/etc/resolv.conf -> /run/systemd/resolve/resolv.conf gui for ethernet connection is 'Automatic Addresses Only' with DNS Servers 8.8.8.8, 8.8.4.4

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