Do you have an autodesk subscription? I had that problem recurring for a couple of months. Not sure if it was the same error but it looks familiar. I had multiple phone support calls over a few days, and they logged in to my machine and were able to get everything fixed. The problem was rooted in my backburner and network settings. Not sure exactly what was going on, but hopefully this is helpful. I tried all of the DIY fixes, but in the end, it took filing a ticket through my subscription account and having them call me to do a remote login.