WHMCS Multisite Provisioning "Unable to Determine Status"

Hi, i follow the guide https://premium.wpmudev.org/project/whmcs-multisite-provisioning/#usage to install WHMCS Multisite Provisioning but having problem at the addon activation in WHMCS. I have upload all the required plugin into the folder in the guide, but i cant activate it. It is "Unable to Determine Status" and there is Download/Buy button instead of "activate" button. Please help.