Setup a vCentre Appliance, VCSA, today and after initial config had to change the IP and Hostname.
From the documentation, all I needed to do was goto the Admin Tab and Toggle the certificate settings to allow the SSL Certificate to be created with the new Hostname & IP, this didn’t work, but I did find someone having a similar problem who pointed me to the fix that worked a treat.
https://communities.vmware.com/thread/447770
Hope this helps someone solve their problem.