There is an issue been identified in VMware Tools 10.3.0 can result in a PSOD or guest network connectivity loss. VMware has released KB57796 for that.
When you run Connect-NsxtServer in the PowerCLI, it may show "Unable to connect to the remote server". Because the error message is a little bit confusing with other login issues. It's not easy to troubleshoot. The actual reason is the NSX-T uses a self-signed certificate, and the PowerCLI cannot accept the certificate automatically. The fix is super easy. You need to set the PowerCLI to ignore the invalid certificate with the following command: Set-PowerCLIConfiguration -Scope User -InvalidCertificateAction:Ignore -Confirm:$false