I just encountered this issue on a fresh format-and-install (not an upgrade) of the public release of 11.1 on a round Mac Pro; when I'd try to connect to either smb:// or afp:// network shares, it would first show the warning dialog asking me if I wanted to connect, then when I clicked Continue, the "Connecting" dialog would sit there forever with the KITT/Cylon animation, never prompting for credentials or connecting.
I tried the kextload to no avail.
@bombich - https://developer.apple.com/forums/profile/bombich nailed the solution in this very thread, - https://developer.apple.com/forums/thread/661437?answerId=646018022#646018022 which is apparently still an issue in 11.1, wow.