Chat issue - meeting host unable to switch from Waiting Room occupants to Everyone in meeting

[NWEOL]

Dear Zoom Community,

This query concerns in-meeting chat.  Hosting a recent meeting of a premium account (which is owned by a large organization), I have had the Participants List and Chat open at the same time while sharing part of my screen.  Hitherto this has not been a problem, however shortly after the start of today's meeting I ceased to be able to communicate with the in-meeting participants.  I appeared to be locked on 'waiting room participants'.  Shortly after the start, as participants were joining, I had sent one message to 'everyone'; the next message went to 'everyone in waiting room' and thereafter, even when no one appeared to be left in the waiting room, I could not switch to communicate with people in the meeting.   Chat messages could still be sent to everyone in the meeting by the other participants.  I tried closing both the chat and the participants list to no avail.  This would appear to be the second major glitch (the first being inaccessible breakout rooms tab) co-incidentally occurring for the first time since the latest Zoom update.   Please could I ask if anyone has any suggestions as to either the cause or a solution for the chat issue? 

Thanks,

NWEOL