When viewing My Inventory view in vRanger, you only see 1 gold key for one (or more) of your hosts. Properly credentialed hosts should show 2 gold keys (1 large and 1 small gold key) for each host that has VMs being backed up on it.
The host(s) in question have not been credentialed which is evidenced by displaying only one gold key on the host icon in My Inventory view.
Right click on the host in question and click on Add Credentials. Type in the user information along with the root password, if only the root user is used then the password only needs to be typed once. If authentication is successful, the host will be properly credentialed which will be evidenced by displaying 2 gold keys (1 large and 1 small) on the host in My Inventory view.
The big gold key represents a license being assigned to the host and the small gold key represents the host being credentialed. If a vCenter is being used then the host itself may not need to be credentialed because the vCenter credentials will allow vRanger to backup VMs from the host and restore VMs to the host without the host being credentialed itself.