VxRail 3.5 setup - hostnames fail to resolve and vCenter hostname :(

Hi All

Having some issues setting the VxRail up for the first time - wondered if anyone could help

I'm browsing to the initial setup URL - 192.168.10.200 and going through the form - I've already decided on names, IP addresses, VLANs etc.

Switch is all configured. And I've even tested connectivity through to DNS servers from the management ports (using my laptop and what will be the ESXi addresses and management server address)

I'm wanting to use an existing vCenter server 6.0U2

I get the following errors when validating my setup:

vCenter server hostname - Can not retrieve external vCenter server certificate. Make sure hostname is correct

VxRail Manager hostname - Can not resolve or resolved with incorrect IP with hostname from provided DNS servers

ESXi hostname prefix - Can not resolve or resolved with incorrect IP with the following ESX hostnames..... all 4 esxi servers....

Thing is - if I chose not to use my own vCenter server the validation comes back as good - strange as I would've thought it would still have issues resolving DNS for the ESXi servers? Unless the setup tries to resolve through the vCenter??