This is not required because backups will run with just the vCenter credentials.
vCenter (VC) credentials are from the Virtual Center and if the server (Host(s)) were added with a simple name verses a FQDN or IP in the VC then that is how they show up in vRanger and name is grayed out if you right-click on it to add credentials. You can’t change the name to FQDN or to IP.
Go to Tools -> Startup Wizard and then Next -> Next to the page where you add Virtual Center(s) and Hosts. Under the Hosts section click on Add and then enter the information (FQDN or IP) with user name and password and then click connect.