Authorization header not working in fetch – React Native

I am making a request to an API that I have on my computer (192.168.1.132) with react native from my phone (in the same network):

fetch('http://192.168.1.132:8000/test', {
  method: 'GET',
  headers: { 'Authorization': 'Bearer 4uFPmkP5326DXcRuHDKjRRrmhdeIBJ'},
  credentials: 'same-origin'
  })
  .then((response) => response.json())
  .then((responseJson) => {
    console.log('RESPONSE: ' + JSON.stringify(responseJson))
  })

But I am sniffing the request and it has not the Authorization header (any other that I put will appear, but not Authorization). In Xcode I have enabled ‘AllowArbitraryLoads’. So my API returns 401 (Unauthorized) because obviously there is no Authorization header. Why is it not included in my request?

Authorization header not working in fetch – React Native