Powershell: Join path issues with copy item

I have the following piece of code:

$ServerPath = \\test\ps
$fullpath = Join-Path $ServerPath "\stackoverflow"

Copy-Item $fullpath "c:\"

It gives me this output:

Cannot find path \test\ps\stackoverflow because it doesn't exist.

Inital \ character is omitted in full path when used with Copy-Item command. but Write-Output prints value correct开发者_运维问答ly.`

I want to join the path, someone please help me with this. Thanks in advance.

Be sure to use quotes when assigning a variable so that PowerShell does not try to execute the command

$ServerPath = '\\test\ps'
$fullpath = Join-Path $ServerPath '\stackoverflow'

Copy-Item $fullpath 'c:\'