"AppName" is damaged and can’t be opened. You should move it to the Bin.
This is a protective mechanism that is letting you know an app's code signature has been altered and therefore may do something not originally designed for (e.g. it may have been altered to include a keylogger). You should actually bin it for safety but if you're 100% sure it's fine and you absolutely need to open it, try these fixes:
FIX 1
xattr -cr /Applications/AppName.app
FIX 2
sudo spctl --master-disable