This is just a very common error when you trying to access the vCenter Server with PowerCLI and when you have an invalid server certificate, probably the first time you are trying to connect with PowerCLI. You can easily fix it by executing a line of command. I hope this will be really useful.
Connect-VIServer Connect-VIServer : 2/20/2019 6:27:50 AM Connect-VIServer Error: Invalid server certificate. Use Set-PowerCLIConfiguration to set the value for the InvalidCertificateAction option to Prompt if you’d like to connect once or to add a permanent exception for this server. Additional Information: Could not establish trust relationship for the SSL/TLS secure channel with authority ‘VCENTER_SERVER’. At line:1 char:1 + Connect-VIServer <VCENTER_IP_ADDRESS_FQDN> + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : SecurityError: (:) [Connect-VIServer], ViSecurityNegotiationException + FullyQualifiedErrorId : Client20_ConnectivityServiceImpl_Reconnect_CertificateError,VMware.VimAutomation.ViCore. Cmdlets.Commands.ConnectVIServer
Just execute below command to ignore the invalid certificate
Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -Confirm:$false
I hope it helps.