Problems advancing PowerPoint slides

[JCG]

I recently upgraded to a new iMac. During two Zoom meetings with 20-plus members since then, I was unable to use the arrow keys to advance my shared PowerPoint slides. Instead I had to use the ultra-sensitive touch pad atop the Magic Mouse.

This problem did not occur the night before last when our guest speaker and I practiced his presentation. Neither does it occur when I practice using my laptop and iPhone as other meeting participants.

Curiously, the arrow keys worked for the first couple of slides last night then quit working for the rest of the meeting. 

I did not have this problem with my old iMac running Catalina. 

Anyone have a clue as to what could be happening?

[Jayesh]

No idea, I have the same problem with an i7 Dell windows laptop. The PPT works fine with the arrow keys but when shared on a zoom call they stop working. The work around is to have the minimized window on the side and close the full screen ( which also does not work when the esc button is pressed) and go to the next slide. Tedious . If some one has a solution would love to hear it.