Body empty sometimes in fetch .body with base64

Hi. im debuggin an APP in Chrome and all is working nice, but when i compile and i test the app, sometimes the fetch is sending the body empty and others the body its ok… in the body there are a base64 string, an image, i dont know if Android have any limitation with this… i have tried with 2 devices.

 const cameraPhoto = await getPhoto({
            resultType: CameraResultType.Uri,
            source: CameraSource.Camera,
            quality: 100
      const base64 = await base64FromPath(cameraPhoto.webPath!);

        //Subo foto al W.S.
        const datos = { imagenBase64: base64, bastidor: "el basti" };
        const miInit = { method: 'POST',
               headers:{'Content-Type': 'application/json', "Authorization": `Bearer ${token}` } ,

      var response=  await fetch(process.env.REACT_APP_URLAPI+APISMARTCARSUBEFOTO,miInit).then(res => res.json())
      .catch(error =>  MuestraAlert(error, TipoAlert.error))
      .then(response =>  MuestraAlert("BIEN", TipoAlert.informacion));