This fix worked for me on macOS Catalina:
• Right-click the app
• Click Show Package Contents
• Open the Contents folder
• Open the MacOS folder
• Open a new Finder window.
• Go to your Applications folder.
• Open the Utilities folder
• Open Terminal
• Type in (without the quotes) "chmod +x " (note the space after +x)
• Go to the first Finder window without hitting enter in Terminal
• Drag the file with the same name as the app (and without an extension), and drop it into the Terminal window.
• Click on the Terminal window and hit enter.
Then you should have permission to open it.
This should be pinned on 1st page