Hi Beverley,
Thanks for your updates.
According to your reply, I'm a little confused about the OWA app for Mac you mentioned. Do you mean it is the Office 365 OWA(https://outlook.office365.com/owa/) I mentioned in my first reply?
If so, what browser are you using to open it? If you change another browser, does the same issue occur?
In addition, some screenshots are helpful for us to know more information about what you encountered. Once you can provide any related information, any updates are appreciated.
Thanks for your understanding.
Best regards,
Kid Yang