CSOMTest.ps1

CLS
<# list .net installed versions
[System.Environment]::Version()
Get-ChildItem 'HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP' -recurse |
Get-ItemProperty -name Version,Release -EA 0 |
Where { $_.PSChildName -match '^(?!S)\p{L}'} |
Select PSChildName, Version, Release
#>
function Using-Object
{
    [CmdletBinding()]
    param (
        [Parameter(Mandatory = $true)]
        [AllowEmptyString()]
        [AllowEmptyCollection()]
        [AllowNull()]
        [Object]
        $InputObject,
 
        [Parameter(Mandatory = $true)]
        [scriptblock]
        $ScriptBlock
    )
 
    try
    {
        . $ScriptBlock
    }
    finally
    {
        if ($null -ne $InputObject -and $InputObject -is [System.IDisposable])
        {
            $InputObject.Dispose()
        }
    }
}

function log([string]$s){
    process {
        Write-Host "$(get-date -format 'yyyy-MM-dd hh:mm:ss.fffffff') $s"
    }
}

$dl1 = 'C:\SOME\FOLDER\2013\Microsoft.SharePoint.Client.Runtime.dll'
$dl2 = 'C:\SOME\FOLDER\2013\Microsoft.SharePoint.Client.dll'
log $dl1
log $dl2

Add-Type -Path $dl1 -ErrorAction Stop
Add-Type -Path $dl2 -ErrorAction Stop

$siteURL = 'https://my/sharepoint/site/'
Using-Object($ctx = New-Object Microsoft.SharePoint.Client.ClientContext($siteURL)){
    $credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials("USERNAME",(ConvertTo-SecureString 'PASSWORD' -AsPlainText -Force))
    $ctx.Credentials = $credentials
    
    log 'connectiong ...'
    try {
        $ctx.ExecuteQuery()
    } catch {
        log $_
        return
    }

    log 'connected!!!'

}