Even after I configure my printer/scanner and scanimage -L being able to successfully identify it, I was not getting any remote scanning to work.

Simple-scan used to complain about unable to locate scanners and scanimage complained about ”unable to load restricted library /usr/share/hplip/scan/plugins/bb_soapht.so”

What fixed it was reinstalling hplip and running sudo hp-plugin -i (and saying Y to everything)