Tried the 35 second fix but machine (Vertuoline Evoluo) remained in double-blink. Turns out it had three separate issues, so below is a combination including several previous fixes. Worked for me so hopefully it helps someone else.
1) Air pocket in water line: Prime it using a turkey baster or clear flex hose. Match the diameter of the tip to the water intake O-ring (mine was red) by wrapping tape around the tip of baster. Force water into the intake slowly, under constant pressure. The water level inside the turkey baster should go down steadily as you do this. Depending on how long since last use, I suggest injecting 1/8 ~ 1/4 cup.
2) Top disc: Any clicking noise is the sound of the wheel trying to spin freely. It must be cleaned until it spins with no effort. Use wet paper towels to clean all grounds out and avoid cutting your fingers on sharp teeth. After mechanical cleaning I turned my machine upside-down and rinsed the top disc out thoroughly under the kitchen sink.
3) Lower pod-holder: This too must be cleaned all around its perimeter to allow reading bar-codes on pods. First use wet paper towels, then a wet q-tip, then a dry q-tip. Get out all the grounds and any brown build-up. Finally rinse under sink.
Tip1: Create an empty test pod. Cut the thin foil top (only) off a used pod, empty it, and clean it out. The barcode on the lower lip remains so use this pod to run test cycles.
Tip2: Place machine on sheetpan with a lip to keep the mess down.
My mom is on her third machine; this time I said no more.