According to the firebase web documentation, it's possible to upload a base64 String with the following code

// Base64 formatted string
const message2 = '5b6p5Y+344GX44G+44GX44Gf77yB44GK44KB44Gn44Go44GG77yB';
uploadString(storageRef, message2, 'base64').then((snapshot) => {
  console.log('Uploaded a base64 string!');
});

I tried to implement this example in react native with the following code

import storage from '@react-native-firebase/storage';

const uploadString = async () => {
    let uploadTask = storage().ref().child('file_name').putString('5b6p5Y+344GX44G+44GX44Gf77yB44GK44KB44Gn44Go44GG77yB', 'base64');

    uploadTask.on(
      storage.TaskEvent.STATE_CHANGED,
      null,
      function (error) {
        console.log('ERROR : ', error);
      },
      function () {
        console.log('upload complete!');
      });
  }

I get an undefined error

ERROR :  [Error: [storage/unknown] An unknown error has occurred.]

I also tried to upload base64 images, blob... nothing is working. Uploading files from the UI is however working. Should I enable something from the console? Am I importing the storage module correctly?