Access to Polls Denied

Hi,

Yesterday I was hosting a meeting with polls.  I arrived to the room and checked the polls and they were there.  I proceeded to start the meeting and I noticed someone signed in as me but I didn't give it much thought.  Then when I tried to launch the polls, it said I didn't have access because I was logged in on another device.  Did that person have access to my polls?  I was surprised that would happen because I was the host of the meeting and this person was temporarily made to be a cohost.