OK. I had this same problem.
It took me four hours…, but it will be quicker for another.
Step 1 - Go to the downloads page, and download Smartware, cloud and whatever else you think might be in play…, (Sorry to be vague. But anyway, probably you have already done this.)
Stap 2a - If you are not completely sure of username/ password, create a new user.
Step 2b - Make sure than user has access to all shared drives and that you create a private drive for that user. This seems to be important.
Step 3 - Turn off your firewall ! At this point, my log-in worked.
Step 4a - Turn on the firewall - it all seemed to work, until I tried to back up - when I got a warning that the drive was not authenticated.
Step 4b - Turn off your firewall ! At this point, my back-up started working.
Step 5 - To be proven yet: I will turn on the firewall again, and see if I can make it all work properly.
P.S. For the connoisseurs - yes, I was watching my firewall all the time in the fours hours until now. And it seemed that everything was Green. So I have not found what I should have allowed. Perhaps it is a very deep protocol exchange under another app? Who knows. I just did not see anything, but decided to go for the nuclear approach anyway as an vanilla test.