Zoom.us - Freeze !!! Please help

Hi,

Everything is ok with using Zoom.us so far when I used my privilege (paid) account in several over-30 people meetings. But problem occurred when I used a non-privileged account (time limited in 40 mins) with a ppt file shared and with a Midi keyboard played at the same time in a 10-people meeting. My iMac was froze twice within 40 mins. It was a very strange experience for me because I have used Zoom for several months with a large number of people by using a paid account. It was absolutely smooth. The config is almost the same in both situations. I have no clue that why the iMac froze with even smaller number of people. However, all the people in the second situation were turned on their cams.

I found someone said there was something called HW Accelerated Video and that thing made the iMac freeze easily. Then I un-click the option in Video setting in Zoom and see what will happen next time.

Any other idea please?

Thanks in advance

Zoom.us - using the most updated version: 5.0.3