Help with playback (Solved)

Looks like most of the notes are way outside the normal bass range - like maybe you aren't accounting for the transposition properly. By default, MuseScore sets up double bass as a concer pitch instrument using the octave-transposing version of the bass clef. If you wish to use a normal bass clef, or a treble clef, you would need to set up the transposition yourself in Staff Properties or else MuseScore will eb trying to play everything an octave too high.