Required Steps:
NOTE: This has been fixed in HPLIP 1.7.1.
Problem: There is a possible problem with HPLIP and PyQT 3.16 which may cause faxing (and other functionality of HPLIP) to stop working.
Workaround: Faxing should work from the command line. Example:
hp-sendfax -n -p <fax queue> -f <fax number> <files>
Workaround 2: KDEprintfax users can follow this guideline:
Settings Configure kdeprintfax System Fax System: "other" Command: "hp-sendfax -pPRINTERNAME -f%number -n %files"