Inappbrowser cant catch the token and goes directly to "about:blank"

Question

I m trying to get the dropbox token. After successfully login, dropbox redirects the url and Inappbrowser goes directly to "about:blank" in the background. I believe token comes for a second but inappbrowser redirects the browser so fast to "about:blank" so the token is lost. I found out when i put a breakpoint in the event listener i can get the token actually. It is really weird. What am i doing wrong ?

connectDropbox() {
      this.$rootScope.$on('$cordovaInAppBrowser:loadstart', (e, event) => {
          if(event.url.indexOf("access_token") > -1){ // when i put here breakpoint i actuall get the token, otherweise not.
            this.TOKEN = this.parseQueryString(event.url).access_token;
            this.uploadXml();
          }
      });
  let dbx = new Dropbox({clientId: this.CLIENT_ID});
  let str = dbx.getAuthenticationUrl("http://localhost");
  this.$cordovaInAppBrowser.open(str, '_blank', this.defaultOptions);
}

My Options for Inappbrowser :

 private defaultOptions = {
      location: 'no',
      clearcache: 'no',
      toolbar: 'no'
    };