报npm ERR! fetch failed https://registry.npmjs.org/grunt-contrib-uglify/-/grunt-c错误

D:\grunttest>npm install
npm WARN package.json demo@0.1.0 No repository field.
npm WARN package.json demo@0.1.0 No README data
npm ERR! fetch failed https://registry.npmjs.org/grunt-contrib-uglify/-/grunt-c
ntrib-uglify-0.2.7.tgz
npm ERR! fetch failed https://registry.npmjs.org/console-browserify/-/console-b
owserify-0.1.6.tgz
^C终止批处理操作吗(Y/N)? ^Y
终止批处理操作吗(Y/N)? y

D:\grunttest>npm config set registry http://registry.npmjs.org/

D:\grunttest>npm install
npm WARN package.json demo@0.1.0 No repository field.
npm WARN package.json demo@0.1.0 No README data

D:\grunttest>grunt
Running "uglify:build" (uglify) task
>> Destination (dest/zepto.min.js) not written because src files were empty.

Done, without errors.