Once you have installed vCenter Server 5.5 with Simple Install or Upgrade from 5.1 to 55, and when you’re connecting to your new environment you are getting a “You do not have permission to login to this server.
To get you up and running fast follow these simple step:
1. Login to the Web client “https://client-hostname:9443/vsphere-client” with firstname.lastname@example.org. Or you can login with vSphere Client.
2. Navigate to vCenter Servers -> Manage -> Permissions, click on the + to add a user. Or with vSphere Client -> Home -> Hosts and Clusters ->Permission, Add Permission.
3. Now add your Domain user or group that you would like to have access to vCenter with the permissions required and click on OK.
4. Try and login with the user you just configured and you should now have access to the vCenter Server.
Related link KB VMware: