Send Button Greyed Out For New Messages

mdalberg Mine also seems to be most prominent when scheudling from Zoom and it launches the Outlook Appointment.  I found just closing the message (red dot) on the mac, after I add my attendees, pops this same prompt "do you want to send invitation?" and is the easiest way to get the message to send when I'm ready.  I've tried toggling between appointment views, hitting about every button in the toolbar, command+enter, etc. nothing works to enable the send button.  

Amazing that Microsoft hasn't fixed this by now