I have this issue when migrating a 6.0 vCenter to 6.5:
ErrorHost name vS-vCenter1.dpsi.jp is not DNS resolvable, but matches the machine certificates. If you do not configure a valid DNS resolvable hostname mapping, then you might not be able to connect to the vCSA afterwards
ResolutionEither update appliance /etc/hosts or /etc/resolv.conf file to properly access DNS servers or update appliance DNS servers with the proper host name mapping. To check if DNS server has record about local host name, execute `dig vS-vCenter1.dpsi.jp +short` locally on the appliance, or `nslookup vS-vCenter1.dpsi.jp` on a windows machine.
The commands suggested work as expected, and DNS records all resolve correctly.
What could the issue be?
On vCSA, can you 'dig -x 192.168.1.11'?
Are all hosts involved querying the same DNS server(s)? If you have more than one, 'dig @192.168.2.2 -x 192.168.1.11', for example. Make sure everything resolves forward and back everywhere.
root@localhost [ ~ ]# dig -x 192.168.1.11
; <<>> DiG 9.10.4-P1 <<>> -x 192.168.1.11
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 59330
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;22.214.171.124.in-addr.arpa. IN PTR
;; ANSWER SECTION:
126.96.36.199.in-addr.arpa. 3600 IN PTR vS-vCenter1.dpsi.jp.
;; Query time: 0 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Mon Nov 28 18:58:34 UTC 2016
;; MSG SIZE rcvd: 87
Only 1 DNS server which is 192.168.1.1 and it returns the correct results. Not sure why it isn't working.