Ensure you are using the Nintendo 3DS AC adapter (Model No. WAP-002 (AUS)). The Nintendo DSi AC adapter is also compatible.
Unplug the AC adapter from the console and electrical outlet and wait approximately 30 seconds before plugging it in again. Ensure the AC adapter is securely connected to both the New Nintendo 2DS XL and the electrical outlet.
If you continue to experience this issue, contact Nintendo Customer Service.