Arduino HID keyboard does not work
Keyboard.press() expects a character, but you are passing a character array. Also Keyboard.press() only presses but does not release the key. Keyboard.releaseAll() can be used to release all keys.

I would try:

Keyboard.press('A') ;  //note the ' instead of "
Keyboard.releaseAll();


or preferably:

Keyboard.write('A');   //handles press and release of basic keys