ytextractor.ExtractorException: Error While getting Youtube Data:Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference

[niteshfel]

ytextractor.ExtractorException: Error While getting Youtube Data:Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference

I found this exception when extract video :
example.ytextractor.YoutubeStreamExtractor.doInBackground(YoutubeStreamExtractor.java:151)
example.ytextractor.YoutubeStreamExtractor.doInBackground(YoutubeStreamExtractor.java:25)

On line number 151 of class YoutubeStreamExtractor
LogUtils.log(Arrays.toString(e.getStackTrace()));
Ex = new ExtractorException("Error While getting Youtube Data:" + e.getMessage());
this.cancel(true);

please check this ASAP @nhCoder