Launching a meeting that someone else schedules

Last night, I was given an imbedded link, password and host code for a meeting for a seminar to connect a small group to a meeting. However, when I opened the link, the "waiting for host to start meeting" window appeared, as the creator did not participate. I could not open the portal, despite having the code.  I extracted the portal code from the link and tried to launch it manually, to no avail. Thee was nowhere to claim the meeting before it was launched. After waiting a while for someone to do so, I launched a new portal and passed the link on to the other participants.

I assume the host code is only viable to transfer ownership once the meeting has started, but is there something I missed here? Can a meeting be opened by anyone other than the creator?