Difficulty starting a meeting I have scheduled

I am a relatively experienced Zoom user, but lately I have had difficulty starting meetings as the software thinks I am already in a meeting and asks me if I want to leave the meeting to join the new one.  I am not aware that I am in a meeting already (none scheduled etc.) and even when I accept that I will need to leave the 'other' meeting to join this one - I can't.  This has only happened in the last 3 months, so I am wondering what has changed.  Is there any way of seeing what meeting I am supposed to be in and managing to get myself out of this?

Thank-you!