Can't get GPS location fix

Some weeks ago Waze started acting up and not finding GPS location.
Then it randomly bounced between on and off, and now I can't get it at all.
GPS test says NO FIX, with 16 satellites in view and 3 in use (though they vary a bit).
Would this be due to a malfunctioning GPS receiver? If so, is it...

Can't get GPS location fix