While connecting to ESXi Server with VMware PowerCLI from one of my server I was keep receiving below error. I wasn't able to connect to ESXi server directly from PowerCLI module. 

@SERVER01 ~ Connect-VIServer ironman.vcloud-lab.com
Connect-VIServer :  Object reference not set to an instance of an object.
At line:1 char:1
+ Connect-VIServer ironman.vcloud-lab.com
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo           : NotSpecified: (:) [Connect-VIServer], NullReferenceException
    + FullyQualifiedErrorId  : System.NullReferenceException,VMware.VimAutomation.ViCore.Cmdlets.Commands.ConnectVIServer

After trying few troubleshooting options I came to know, this issue occurs due to old version of the VMware PowerCLI I was using, possibly due to bugs in older version, I went to the Powershell Gallary (psgallery) website and checked the latest version. I found I was running way back older version of PowerCLI.

https://www.powershellgallery.com/packages/VMware.PowerCLI/

From commands, I can check the current version of installed VMware.PowerCLI module. Next I can find latest PowerCLI module available online. Module can be easily updated with Update-Module.

@SERVER01 ~ Get-PowerCLIVersion
@SERVER01 ~ Find-Module VMware.PowerCLI
@SERVER01 ~ Update-Module VMware.PowerCLI -Scope CurrentUser

Once Module is downloaded and uploaded locally successfully from PSGallery repository, Checked the command again to verify the PowerCLI version. Alternatively to check latest version Get-Module -List command can also be used. In the last verify if I am able to connect to ESXi server.

@SERVER01 ~ Get-PowerCLIVersion
@SERVER01 ~ Connect-VIServer ironman.vcloud-lab.com

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