I had to redeploy a vCenter Server Appliance recently and got an error when opening vCenter: sysimage.fault.SSLCertificateError.
This is caused by the certificate on the vCenter Server changing. This causes the Upgrade Manager needing to be re-registered with the vCenter Server. Luckily, VMware provides a utility to do just that. Go to your vCenter Upgrade Manager Server (The appliance does not include this, so it will typically be installed on a separate Windows Server).
Go to “C:\Program Files (x86)\VMware\Infrastructure\Update Manager” and open the file “VMwareUpdateManagerUtility”.