The first step is to cycle white distilled vinegar through the system several times. This will dissolve accumulated mineral deposits.

If this doesn't resolve the problem try probing the delivery port(just above where the coffee capsule is placed) with a pointed probe such as a dental probe. After that blast the port with canned compressed air. This should clear the delivery port.

Afterward run several cycles of filtered water through the system to clear out the debris and the vinegar aroma.

Enjoy good coffee again.