Zoom Meeting Connection Issue: can't see/view each other (i.e participant and host) on Zoom

I am reaching out regarding an issue.
In Zoom meeting
From Participant's account, he/she  clicked  "Join Session" or "Join meeting" or "meeting link" before the scheduled time but showing that the meeting has not started.
but when checked with host,  he/she joined the meeting.

they were not able to see/view on Zoom when both the participant and coach joined the session.

As a result,
We are requesting your assistance in investigating this matter further to determine, 
Why the participant was not able to connect to the meeting, despite both parties joining the session.

Thank you for your prompt attention to this matter.