This keeps happening to me. I start a scheduled meeting from either Zoom.us or my Zoom client, but no one joins it. Then I get an email from Zoom saying that people have joined my meeting. Since they are not in my current meeting, I have to end the meeting and start it all over again using the link the Zoom email.
I checked the meeting id -- they are the same (in the email and in my Zoom account). I also have disabled "participants can join before host." I don't know what I'm doing wrong, but I find this so nerve-wracking when I'm supposed to be hosting.