upload image using file transfer ionic 3 not work on iOS - asp.net

Question

upload image using file transfer in ionic 3 works fine on android,
but give me error on iOS when try it in simulator ..
* this is the error:
My Ionic Code:
chooseImageFromGallery()
{
this.type="0"
const options: CameraOptions = {
quality: 60,
destinationType: this.camera.DestinationType.FILE_URI,
encodingType: this.camera.EncodingType.JPEG,
mediaType: this.camera.MediaType.PICTURE,
saveToPhotoAlbum:true,
sourceType:0
}
this.camera.getPicture(options)
.then((imageData) => {
if (this.platform.is('ios'))
{
this.base64Image = imageData;
}
else
{
this.base64Image = imageData;
}
this.uploadimage(); // this function to upload img to server
},
(err) => {
}).then((path)=>{
})
}
uploadimage(){
this.photoSrc="";
this.translate.get("uploading Image...").subscribe(
value => {
this.sucesss=false
const fileTransfer: FileTransferObject = this.transfer.create();
let options: FileUploadOptions = {
fileKey: "file",
fileName:'test',
chunkedMode:false,
mimeType:"image/jpeg",
headers:{
Connection:"close"
},
httpMethod: "POST",
}
//------------ android ------------//
this.base64Image =this.base64Image
//------------ ios ------------//
//this.base64Image =this.base64Image.substring(28)
fileTransfer.upload(this.base64Image,encodeURI('mydomain/api/Product/upload'), options)
.then((data:any) => {
alert("upload success ")
}, (err) => {
this.translate.get( "error in upload Data").subscribe(
value => {
this.service.presentToast(value,2000)
}
)
})
})
}
using asp.net api2 .. My server Code :
[HttpPost]
[Route("upload")]
[AllowAnonymous]
public HttpResponseMessage uploadImage()
{
var request = HttpContext.Current.Request;
if (Request.Content.IsMimeMultipartContent())
{
foreach (string file in request.Files)
{
var postedFile = request.Files[file];
if (postedFile != null && postedFile.ContentLength > 0)
{
string root = HttpContext.Current.Server.MapPath("~/ServerImg");
root = root + "/" + postedFile.FileName;
postedFile.SaveAs(root);
//Save post to DB
return Request.CreateResponse(HttpStatusCode.Found, new
{
error = false,
status = "created",
path = root
});
}
else
{
return Request.CreateResponse(HttpStatusCode.NotFound, new
{
error = true
});
}
// var title = request.Params["title"];
}
// }
return null;
}
else
{
return Request.CreateResponse(HttpStatusCode.Forbidden, new
{
error = true
});
}
}
I spend more than 4 days.. but nothing is work for me ..
And this code works fine on Android but not iOS I don't know what's the wrong, I tried real iPhone and Xcode simulator and not worked
always upload error {"code":3... "http_status":500,..
Can anyone Help me please...