I am using vagrant 1.9.*, where it is not allowing me to login in to vagrant using my credentials related to atlas.hashicorp.com because recently they[vagrant team] changed the process of login in to vagrant. From vagrant version 2.* we have to login using credentials related to vagrantcloud.com and token generated by that website. Now I am successfully logged in to vagrant using my command line. Thanks for the viewers who tried to answer my question !!!