Does my plug-in work with Sound Studio?
Third-party audio unit plug-ins need to be 64-bit and "sandbox-safe" in order to work with the Mac's newer operating systems and with Sound Studio. "Sandbox-safe" means that the plug-in has to have been updated by its maker in order to comply with Apple's "sandboxing" security measures.
If your plug-in is not working as expected, check for updates from the maker and check the plug-in's release notes for compatibility with your macOS version. If it's a sandboxing issue, then you should receive an error alert about your plug-in not being sandbox-safe when you try to launch the plug-in in Sound Studio. If you receive a different error message, try quitting and relaunching Sound Studio and even restarting your computer to ensure it's not just a temporary glitch.