Water leaking from the group head while steaming usually isn't a fault — check these first:

  1. Portafilter seated? Remove, wipe the gasket, re-seat firmly.
  2. Gasket condition: a hard or cracked group gasket leaks under pressure. Gaskets are wear items; replacements are inexpensive.
  3. Overfilled basket: coffee touching the shower screen breaks the seal.

If it leaks constantly even when idle, stop using the machine and raise a warranty request with a short video.