A requirement not everyone is aware of is the availability of a DNS server before vCenter Server appliance can be deployed. If you start building a new infrastructure from scratch, you might have just a few ESXi hosts before deloying the VCSA.
At stage 2 of the vSphere 6.5 vCenter Server Appliance (VCSA) installation an error is shown:
“Unable to proceed with stage 2 of the deployment process.” The installer is unable to connect to the vCenter Appliance Management interface
This problem is caused because there is no DNS A (and DNS PTR) record for the VCSA.
So make sure to create these records in the DNS server you have typed in during the configuration of the appliance deployment.