It's been a while since I played with the VMware vCenter Server Appliance, so it took a second for me to get used to it again. One thing that kept haunting me is logging in after changing the IP address to a static IP. By default, the vCSA choses an IP address using DHCP. You may then go in and change it to a static IP in the network tab of the vCSA configuration GUI. However, once you do that, it breaks SSO (single sign on).
To fix this, click on the Admin tab in https://[vCenter_IP]:5480 and choose to regenerate certificates. Then click on the submit button and finally reboot the appliance. That should allow you to login.