Nintendo Network maintenance has been scheduled for this evening although worry not, as it will be over before you know it.
Both Wii U and 3DS will be affected today, Monday 23rd June, between 23:30 – 23:35 BST, meaning that you may encounter downtime for a meagre five minutes while either accessing the Nintendo eShop or trying to speed your way around a track in Mario Kart 8.
Nintendo recently indicated that the regular Nintendo Network maintenance schedule is set to change, although have not yet confirmed any finalised details.