Microsoft Office plug-in

Microsoft Office plug-in

A while ago, I installed the Zoho CRM Plug-in for Microsoft Office.
I just went to use it, and got a message "Your trial has expired.  Please subscribe now to continue working".  I didn't know a subscription (other than to Zoho CRM) was necessary.  It's not listed on the pricing schedule.  What do I need to do to able to use this plug-in?
Thanks.
Gary