During the process of restoring the vCenter Server Appliance from a backup image, you cannot use vCenter Single Sign-On authentication. You must use local authentication until the appliance is fully configured.

When you restore your vCenter Server Appliance from a backup file, it begins in an unconfigured state. During this time, you must use local authentication to access the Management API. When you use local authentication, do not use the vSphere Automation API endpoint. Instead, you must connect your client to port 5480 of the appliance.

When you use local authentication you must pass user name and password credentials with each method invocation. Use credentials that are known to the guest operating system of the appliance.