This error occurs when the water tank does not fill automatically on machines with a direct water supply. To resolve the issue: 

1. Remove the water tank and ensure there are no blockages or debris that would stop water passing through.
2. Ensure the mains water is turned on at the plumbing.
3. If these are not the causes, turn off the machine and disconnect from the power source.
4. Wait 30 seconds.
5. Replace all of the components back into the machine.
6. Plug the machine back into a working power source and turn it on.

If this does not resolve the problem, please contact us using the Live Chat in the bottom right or call our Nespresso team on 0808 100 5000.