Can't create file on IOS

[Neoxs]

I am trying to createFile using RNFetchBlob, on Android is working well yet on IOS i am facing lot of issue using the same method on IOS

RNFetchBlob.fs
          .createFile(path, base64PngImage[1], "base64")
          .then(res => {
            console.log("File : ", res);
            confirmClosing(true);
          })
          .catch(error => {
            console.log("err", error);
          });

From the logs i am getting File : [null]
Also after checking the directory i found that all files are being saved empty