Issue sending xsi-event heartbeat

I am having issues sending heartbeat commands to xsi-events to keep the channel alive.   I am getting the response "<ErrorInfo xmlns="http://schema.broadsoft.com/xsi"><summaryEnglish>Missing entity body in request</summaryEnglish><errorCode>1102</errorCode></ErrorInfo>". 

I am sending a put request to the below url format with no content ( maybe i need to send something with the url? )..  Any help is greatly appreciated.

https://hostname/com.broadsoft.xsi-events/v2.0/channel/channelid/heartbe...