on Webex Meetings 39.8.3.902 for Mac on macOS 10.15.3, the "Join a Meeting" text entry field is a multi-line field, so you can for example cut and paste a meeting number with newline characters by accident into it, and then you will get an "invalid meeting number" error if you have pasted multiple lines by accident somehow. It will not be very obvious because the entry field only displays a single line, and you will think the meeting number is just invalid.
For example you can currently paste into it:
000 000 000
111 111 111
222 222 222
The "join a meeting" field in the macOS app should only be a single line field.
