[LockedApp] can’t be opened because it is from an unidentified developer. Your security preferences allow installation of only apps from the App Store and identified developers.
This is actually a macOS Gatekeeper issue try these steps:
To resolute Gatekeeper issues on macOS Sierra you might have to partially or completely disable Gatekeeper checks.
Option I For a certain application run in Terminal:
sudo xattr -rd com.apple.quarantine /Applications/[LockedApp].app
Option II To disable checks globally run in Terminal:
sudo spctl --master-disable
xattr /Applications/[LockedApp].app