Participants having trouble accessing meeting

Hi jst3005, 

U always can test zoom meeting using this links zoom : http://zoom.us/test hope it helps.

I signed in but still not in

A common reason that the message a host has another meeting in progress occurs is due to Zoom's join before host feature being enabled.
Details on the feature: https://support.zoom.us/hc/articles/202828525-Allow-participants-to-join-before-host

For example, lets say you have meeting A and meeting B, both with join before host enabled. If participant 1 joins meeting A, as long as that meeting is active participants attempting to join meeting B will be presented with this message. 

Some ways to catch if this is the case

1. Leveraging Zoom's feature to receive email notifications if an attendee joins before you:
   https://support.zoom.us/hc/articles/201362713-Receiving-email-notifications-when-attendees-join-meeting-before-host
2. Checking your meeting list at the following page. If a meeting is active, you'll see a video camera icon next to the meeting with options to join or end the meeting:
   https://zoom.us/meeting#/upcoming
3. If you are the meeting host of both meetings and try to start Meeting B in the above case, you will receive an option to close Meeting A and start Meeting B

Hopefully this helps!