Installation of v4.0

When attempting to install the new version 4.0, I receive this Hub message under sections Apps, Featured, and Muse Sounds for MuseScore:

"MuseHub is having trouble connecting. Please check your internet connection and ensure any firewall you have is set correctly"

Now, what does that mean?

My internet is working and has worked superbly for a long time. Why do I get this message with your new install and what do you mean by "set correctly"?