Joining a meeting

[Marilyn-z]

I have been using zoom for years.  Now my attendees cannot join my meeting.  I send them the meeting invitation with all the necessary information, but when they try to enter, they receive a message which says I am already in a meeting.  This is not true.  I am waiting for them to enter the "waiting room" but they cannot.  

What is wrong?

How can I fix this?