Yesterday I could not access these discussions on Firefox, but Chrome worked.
Today I tried four different web browsers on my Mac and I could get to the discussions, but I could not sign in nor reply to a message. I kept getting a security risk error that did not let me bypass.
Right now I am using Firefox on Windows 10, and so far it is working. We'll see after I click Post.
I don't have any other reports of Community access failures, but please keep us informed if things do not improve there.