Trying to send Key Inputs - Uncaught Error: ERR 0x3401 in function "tap"

Hi,
im trying to send keyinputs using a PuckJS ( 2v19 (c) 2021 G.Williams).

//http://www.espruino.com/BLE+Keyboard
var kb = require("ble_hid_keyboard");
NRF.setServices(undefined, { hid : kb.report });
function btnPressed() {
  kb.tap(kb.KEY.A, kb.MODIFY.LEFT_GUI, kb.MODIFY.LEFT_ALT);
}
setWatch(btnPressed, BTN, {edge:"rising",repeat:true,debounce:50});

However, it throws this error, on every puck button press:

BLE Connected, queueing BLE restart for later
Uncaught Error: ERR 0x3401 (:3272)
at line 1 col 104
...0,0,0],function(){a&&a()})})
in function "tap" called from line 7 col 56
kb.tap(kb.KEY.A, kb.MODIFY.LEFT_GUI, kb.MODIFY.LEFT_ALT);
in function called from system

Any ideas? Im using basically the same code as from the example and other forum threads e.g https://forum.espruino.com/conversations/371473/#comment16333536

No idea why its not working.