Is the Nintendo Switch console recognising the controller?
Check whether the controllers are properly connected to or paired to the console.
Is the game card slot or microSD card slot dirty?
Wipe any dirt away with a soft, dry cloth.
Make sure to wipe the slots gently to avoid damaging them.
The Nintendo Switch console may be frozen.
If the console freezes and won't respond to any input, hold the POWER Button for 12 seconds or more to turn the console off.
Then, turn the console on again.