Nespresso Citiz, Inissia and Pixie: Both lights blinking after holding Espresso and Lungo together for 3 seconds (machine on)

What Nespresso says to do

1. Before entering the mode: remove the capsule, empty the drip tray and capsule container, fill the tank with 0.5 L of water plus one Nespresso descaling liquid, and put a container of at least 1 L under the outlet (the Pixie manual says 0.6 L).
2. Press Lungo and wait until the tank is empty; pour the collected solution back into the tank and do it again.
3. Rinse and refill the tank with drinking water and run it through again to rinse.
4. To leave descaling mode, press Espresso and Lungo together for 3 seconds.

From CitiZ — My Machine (user manual): Energy saving mode, First use, Coffee preparation, Emptying the system, Reset to factory settings, Descaling and Troubleshooting and Inissia (user manual): Energy saving mode, Coffee preparation, Emptying the system, Reset to factory settings, Descaling and Troubleshooting and Pixie — My Machine (user manual): First use, Coffee preparation, Energy saving mode, Emptying the system, Reset to factory settings, Descaling and Troubleshooting. This is the Citiz, Inissia and Pixie’s pattern; another Nespresso machine may use the same light for something else — check the manual for your model.