Playback Octaves Above or Below

Hi! Ever since a few weeks ago, my Musescore 4 has been experiencing major playback issues, practically rendering it useless. In the playback, the written notation is always played an octave above or below, and in some pieces, in a different tempo (dramatically slow or fast). I have tried uninstalling, changing my I/O setting, opening my mixer, but nothing has worked and I do not know what to do. Please let me know if there is a solution!