About: When granting TeamViewer access on a MacOS Catalina, your partner will only see gray background and will not have control to your computer. To resolve this issue, you will need to allow "Screen Recording" and "Accessibility" for TeamViewer under the "Security & Privacy" menu.
Step 1: Click on the Apple icon > System Preferences > Security & Privacy
Step 2: Click on the "Lock" icon to unlock > Screen Recording > tick or check TeamViewer
Step 3: While still in Security & Privacy > Privacy > select "Accessibility" > tick/check all instances of TeamViewer
Finish: Close the Security & Privacy window