Host's Zoom Connection Stopped

I am hosting a meeting and sharing my screen and videos.  Almost two hours into the meeting the sharing stops and I am no longer the host but a participant with no controls.  I can unmute myself and talk to others but I am disconnected as the host and have to log back in.  This has happened twice using the same device in about the same amount of time.  The first time there was a dialog box hidden behind other open windows that some one else had logged in using my id.  But I was the only one logged in.  I restarted my laptop and logged back in to get reconnected.  I logged into a different device and did not have this problem.  What could be causing the issue?  Any ideas?