I have run the build on another machine, the build gives the same error.
Edit : From the machine I can download the file in the error message without any issues when I use e.g., wget
E: Failed to fetch http://ports.ubuntu.com/pool/universe/f/fping/fping_5.1-1_arm64.deb Could not resolve 'ports.ubuntu.com'
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
wget http://ports.ubuntu.com/pool/universe/f/fping/fping_5.1-1_arm64.deb
Downloads the file no problem...