It's not easy to help without any details.
Anyway, one common issue is that DNS has not been configured as required. Did you create a DNS entry (Forward, and Reverse) for the vCSA?
There may be many reasons as the cause of your problem. please inform more details form error logs, but also note this, many times it's related to the FQDN / IP address of System Name of VC/PSC. I think you should consider its DNS lookup in first boot step of installation.Please mark my comment as the Correct Answer if this solution resolved your problem