Can't sign in to webinar

I had registered for an Adobe Connect webinar that was supposed to start at 10amPT/1pm ET (so, five minutes ago). When I click the link in the reminder email which is supposed to guide me to the webinar, I'm told the session has already ended.

Also, I wanted to cancel another session I had signed up for, but the cancellation link in the email is dead/request cannot be processed.

Any help would be highly appreciated.