Musehub won't download sounds

I have been using Musescore 4 just fine for the past two months. I had all the sound libraries installed and everything.

Today I opened up the Musehub app to discover that I could also download other stuff like Reverb effects and Chorus, etc., and so I did. I also saw that Musescore needed an update, so I clicked for it to be updated.

However, its been about five hours now, and the downloads aren't going anymore. And for some reason, all my previous downloads of the Musescore sounds, like the Orchestra, were all now in the process of downloading, even though they already were downloaded. 

I know the downloads aren't going anywhere, because it says above the downloading bar 'Unknown zero KB/second', which means no downloads are going on.

I have no idea what to do, and it's really frustrating because now I can't use Musescore at all now, because all the sounds aren't there, because they're still downloading. I tried uninstalling Musehub and ejecting it and all that, but the same exact thing shows up.

Please help!