My Guest Gets Network Bandwidth is Low Messge

Hello,

I do executive coaching for nonprofits. When I set up meetings with my individual clients, they often lag and get the Network Bandwidth is Low message on their screen.  They say it doesn't happen in other meetings.  When I go to other people's meetings, I do not lag.

So my question is, how to I know if a guests lag is on their end of internet connections versus mine?  Of does it have something to do with the way my zoom account is set up?  Any ideas and guidance is greatly appreciated.