How to fix that app can't open on macOS Catalina?
After upgrading to macOS Catalina, some mac users feedback that MusicPlus "can't be opened because Apple cannot check it for malicious software". A dialog box pops up, click "OK" button and the application will close.
Download install file (zip): https://dl.musicplus.io/MusicPlus.app.zip
Extract then copy .app file to /Applications in Finder,
Right click the app icon -> choose Open
- click Open button in the pop-up window