I want to share a map with two people from a client company who are not yet Mindmanager users. They've seen a map I created about their company and are impressed. We agreed that they will sign up for the trial version for now so they can look at and edit it to prepare to present it to a wider audience in the company. If others are as impressed as they are, they will initiate the purchase of the software for the company. When I tried to share the map with them, I got a message that the emails were not sent because "your license quota for sharing was exceeded". What does this mean?