What to do about "Feature is not available for current account EditCallQueueRoutingOptions"

While trying out the API in the developers section of "Try It Out", I am trying the "Update Call Handling Rules". What is it that I need to do to not get the following error "Feature is not available for current account EditCallQueueRoutingOptions". Basically I am trying to use the API to update the unconditional forwarding phone number. I noticed there is a feature flag called "EditExtensionAnsweringRules". Not sure if that has something to do with it, and either way is there some place I need to add this feature?