I had 30 delegates in my session and I split them out into 6 groups to work on an exercise which went fine. However, when I clicked on the end breakout rooms button, the countdown happened and everything at my end looked as though it was going fine. All of the delegates however remained locked in their respective breakout rooms and as they could not hear me I had no was of communicating with them. I ended up have to end the session and contact everyone by email asking them to log back in. For a commercial paid for event this was extremely embarrassing and I would like to find out if I did something wrong or is this a glitch that has happened for others please?