Nintendo has recently decided that there will be a new extraordinary maintenance related to Switch online services, for May 25 and 30 of the same month. Just below, the date and time of the temporary stop, including for Europe (including Italy).

Services impacted
Nintendo Switch: online play (unspecified games)

Times
Europe: May 25th (2.50AM to 4.30AM)
UK: May 25th (1.50AM to 3.30AM)
North America (ET): May 24th (8.50PM to 10.30PM)
North America (PT): May 24th (5.50PM to 7.30PM)
Japan: May 25th (9.50AM to 11.30AM)

***

Services impacted
Nintendo Switch: online play (unspecified games)

Times
Europe: May 30th (3.50AM to 5.30AM)
UK: May 30th (2.50AM to 4.30AM)
North America (ET): May 29th (9.50PM to 11.30PM)
North America (PT): May 29th (6.50PM to 8.30PM)
Japan: May 30th (10.50AM to 12.30PM)

Source: GoNintendo