How can I get my powershell script to post into prtg?

I have wrote a PowerShell script to use the "HTTP Push Data Advanced" sensor:

$prtgresult = '<prtg>
            <result>
            <channel>Message</channel>
            <value>1</value>
            </result>
            <Text>This_is_the_error</Text>
            </prtg> '

Add-Type -AssemblyName system.web
$Answer = Invoke-WebRequest `
   -method "POST" `
   -URI ("http://***IPof PRTG_Server***:5050/***Token***") `
   -ContentType "text/xml" `
   -Body ([System.Web.HttpUtility]:: UrlEncode.($prtgresult)) `
   -usebasicparsing
if ($answer.statuscode -ne 200) {
   write-warning "Request to PRTG failed"
   exit 1
}
else {
   $answer.content
}

I get back a message saying it matched 1 sensor but the sensor is saying "No Data" (I tried adding the HTTP Push Count with the same Token and to matched 2 sensors and I could see it in the Push Count log as picking it up) so I'm now completely stuck and I'm sure I've missed something but I can't figure out what :(

The end result should be that whenever the sensor receives the push message it triggers a "Change Notification" to alert our out of hours support team with the contents on the Text Tag.

http powershell prtg