Most often, this happens when the person using our Web site doesn't complete the process of reserving the conference by selecting "confirm this conference".  It is very important to follow the prompts all the way through the process until our system reads "confirmed conference".  Please visit the Conference Manager page of our site well in advance of your scheduled conference time and verify that the upcoming conference is displayed there.  Also, you may wish to take advantage of our e-mail invitations and confirmations feature to gain a measure of confidence that the conference is truly reserved on our server.