I have been using TeamViewer to remotely share my mother's computer screen for some time. She has an iMac and I have a MacBook Pro. Both are running the latest version of macOS and TeamViewer. However, in the last few months, TeamViewer has stopped working properly for us. When I login to her computer, I can see her menu bar, at the top of the window, but the rest of her screen is just gray. I cannot see any of here windows, desctop, etc. Other than the menu bar, I can see nothing of what is on her screen. As an experiment, I tried to share my screen with her and she had the same result.
If I deselect "Remove Wallpaper" in the View menu, then I can see her desktop picture, but I still can't see any of the open windows or icons on her desktop.
On the other hand, I do not have this problem when I use TeamViewer to login to my office computer. It's running Windows 10.
So, can anyone tell me what is going wrong with my connection to my mother's commputer?