Nintendo has announced on its official page that the next Monday and Tuesday will be a controlled maintenance for its services. In particular, Monday will only affect Nintendo Switch and will run from 2 pm to 5 pm, involving all network services. In fact, "during the scheduled maintenance period specified below, some network services may not To be available." ThereTuesday's maintenance, however, will affect Nintendo's eShop on Switches, 3DS and Wii U, with jobs taking place from 2am to 4pm Italian. "During scheduled maintenance, all network services will not be available," says Kyoto House, referring to eShop. You can see the official page at this link.