It seems that a court has ordered Amazon to deliver only essential products [0], and Amazon's reaction is to suspend all deliveries.
They write in their other tweets [1] that the decision is based on (i) the fine of €1M per infraction imposed by the court, and (ii) the risk of contravening the decision being high due to complex logistics.
I thought the court had ordered them to cease delivering non-essentials, but left the decision of whether to continue shipping essentials or to close altogether up to Amazon.
EDIT: I read elsewhere that it was a million euros per day, not per infraction. Much more reasonable.