BLE to Arduino Nano Sense


I’m trying to connect to an Arduino Nano BLE Sense using BLE from Thunkable X.

I have been following the tutorial on YouTube
The code for the Sense I have used CallBackLED from the ArduinoBLE > Peripheral example library. This will connect the board using the LightBlue app recommended in the video and will show receipt of messages from the app to the board.
On the Thunkable side the Arduino shows connection with the Thunkable app and the app will show connection to the board. But when I try to send a value the message “Can’t write the characteristic provided” error comes up. There is no receipt of anything on the board’s serial.

Any ideas on how to solve this?