Water leaks from the group head around the portafilter during extraction.

Simple checks:

• Clean group and portafilter: Wipe the group rim and portafilter gasket area. Remove coffee grounds and oils.
• Check lock-in angle: If the portafilter rotates too far or not far enough, the gasket may be worn or the lugs damaged.

Replace group gasket:

• Remove shower screen: Unscrew and remove the shower screen and dispersion plate.
• Extract old gasket: Use a gasket pick or small screwdriver to pry out the old group gasket carefully.
• Clean groove: Remove coffee residue and scale from the gasket groove.
• Install new gasket: Fit a new Ascaso group gasket of the correct size, ensuring it seats evenly.
• Reassemble: Reinstall the dispersion plate and shower screen, then test with the portafilter.