Question about Sage the Barista Touch Impress™ Stainless Steel

Unfortunately, I have problems with the extraction. The machine is new, only a few days old. After a few espresso settings, it worked. Now, after about 10 espressos, no more drops are coming through the portafilter. The grind is still the same as it was before (20), same portafilter (single-walled) and same beans - so no new pack of beans either. These are about a month old. Now not a drop gets through during extraction. Everything goes straight into the drip tray and it still says the flow time is ok. Is it possible that the machine does not differentiate whether the coffee runs through the portafilter or straight into the drip tray when measuring the flow rate? The coffee should not be ground too finely, it has worked so far. And if it is too fine, shouldn't the machine complain? Isn't it strange that the machine doesn't notice this and everything just goes down the back into the drip tray?