Ionic inappbrowser return badReqeust for iOS

Ionic Framework ionic-v3
#1

the other web site doesn’t problem but for certain web browser that I want to show is not working.

it says error
Bad Request
16

I don’t know why…

const options : InAppBrowserOptions={
      location:'yes',
      clearcache:'yes',
      clearsessioncache:'yes'
      // mediaPlaybackRequiresUserAction:'yes',
      // hardwareback:'yes'
    }
    console.log("constructor");

    this.url="http://www.kmca.or.kr";
    let target = '_self'
    const browser = this.inapp.create(this.url, target)
    browser.on("loadstart")
       .subscribe(
          event => {
            console.log("loadstop -->",event); .....
#2