clicktocall not working in Chrome (no call option when right clicking)

I have installed the clicktocall Chrome plugin, it seems to be installed fine, I can logon and my details look fine. However, when I select and right-click on a phone number on a webpage, there is no "Call..." option in the context menu
What am I doing wrong?
Jacques Schenk (jacques.schenk@zrefinery.nl)