Play doesn't work in MacBook Pro

The play button and space bar don't work as other functions, such as synthesizer or mixer. They just appear in grey (they seem to be blocked). This has been like this for about 5 months now, and I've already uninstalled and installed and uploaded the programm several times (now I have Musescore 3.5.2). I've also uploaded the Mac's software recently (I currently have the MacOs Catalina version 10.15.7) and I don't know what else to do, as it doesn't work at all, so I hope you can help me.