DIAGNOSIS The most common cause is a clogged exit needle, leading to a slow drip that cools before it hits the cup. Secondary cause is massive internal scale insulating the heating element.
FIX First, clear the exit needle. Unplug, open the lid, and look at the bottom needle inside the pod holder. Use the cleaning tool to gently poke up into the needle to dislodge any coffee or film. Then, run a water-only brew cycle into a mug—feel the water temperature immediately. It should be very hot.
IF THAT DIDN'T WORK Internal scale is the culprit. Descale immediately. If the water is still lukewarm after descaling, the thermostat may be failing, which requires a service call.
HEADS UP The 'Strong' button only affects brew time/strength, not temperature. Always use the hottest setting (default). Pre-heating the machine by running a water-only cycle before your first pod of the day can also help, especially if it's been idle.