vsan.observer VSAN-CLUSTER --run-webserver --force %admin%@%vCenter%

OpenSSL::X509::CertificateError: error getting time

then you can just add the –no-https at the near end of the script like

vsan.observer VSAN-CLUSTER --run-webserver --force --no-https %admin%@%vCenter%

Then load

http://vCenterServer_hostname_or_IP_Address:8010