S2421HN, gives error after adding MS Teams to MacBook Pro

Have a MacBook Pro 15" and have had two monitors attached for years. One is an Acer, and the other a Dell S2421HN. I keep the laptop closed and use the monitors as extended displays all the time (the Acer is probably set as the main display). The only change I made recently is to add MS Teams as Skype is going away. Now, unless I have the laptop cracked open about two inches, the Dell monitor won't display and gives me a message about the display settings. "The current input timing is not supported by the monitor display. Please change your input timing to 1920 x 1080, 60Hz or any other monitor listed timing as per the monitor specifications.'

I can't set the display setting for the Dell to those values unless the laptop is open; otherwise it shows me fewer selections. I tried resetting the Dell monitor to no avail and unplugged the monitor and plugged it back in. There are no updates for the display drivers and my Mac is up to date.

I was told that Privacy Permission changes are needed after adding Teams, but even if I don't have Teams open at all, the Dell goes dark, all my open apps move to the Acer monitor, and the Dell gives me that message when I close the laptop. I obviously can't see what is displaying on the laptop when it is closed, but the apps from the Acer move to it. Also, I had the Dock set to display on the bottom so is always on the laptop screen now so I can't get to any apps when it is closed. It used to be on the bottom of whichever extended monitor the cursor was on. If I move the Dock to the left side of the screen, it is visible when I close the laptop.

I have had this same setup for months and months with no problems, until the latest Mac update and I added the Teams app