Notes are not heard

Hello mates!
I downloaded a music sheet as mscz from this link: https://musescore.com/user/14045951/scores/5938988
but the entire first staff is not being read by Musescore. It is just silence while the rest of the instruments are played perfectly fine. I went to the inspektor and unckecked ''play'' then checked it again, but it did not help at all. I also tried the mixer, but the volume is already on 100%.
Why can't the first staff be played???

Thanks in advance for helping me out!