Custom advanced sensor for Exchange Powershell

I am trying to make a custom advanced sensor to monitor MS Exchange status, however, the xml seems cannot be regonized by PRTG server.

I created 2 testing scripts, both of them got valid output on Windows Powershell. But PRTG server could not regonize the script 1 with error messgae

"Error reading response: Invalid XML (XML Parser mismatch: Wanted </<<<>, got </prtg>)"

Here is my testing ps scripts

1) With Exchange powershell imported

$session = new-pssession -ConfigurationName "Microsoft.Exchange" -ConnectionUri "http://TESTEXCH01/Powershell" -Authentication Kerberos
import-pssession -Session $session -AllowClobber -DisableNameChecking | out-null

Write-Host "<prtg>"
Write-Host "<result>"
Write-Host "<channel>Test Channel</channel>"
Write-Host "<value>0</value>"
Write-Host "</result>"
Write-Host "</prtg>"

remove-pssession -Session $session

2) Without Exchange powershell imported

Write-Host "<prtg>"
Write-Host "<result>"
Write-Host "<channel>Test Channel</channel>"
Write-Host "<value>0</value>"
Write-Host "</result>"
Write-Host "</prtg>"

Can anymore help please?

custom-sensor exchange-powershell prtg