Screen Sharing not working to iPhone

In a meeting with 4 participants, two on ethernet connected iMacs and two on iPhones connected to the same wifi network, one of the iPhones could only sporadically received shared screens.  In the other instances their screen went black and a spinning wheel with a notice that a screen was being shared remained as long as the screen sharing was going on.  On the other iPhone (the Host) that black screen, wheel and notice briefly appeared but was quickly replaced by the shared screen.  Both iPhones are running OS 15.5.  On the iPhone with the problem it seemed that it worked properly for one or two sharings after someone else joined or left, but then stopped working.  Is there a setting I am missing?