I have dug around this issue and looked at common causes, but I would hope someone has struck this as nothing fixes it, however I have a good handle on the issue but not the info to fix it.
Environment : Corperate locked down Windows 2016 environment DNS wise, but it does have access to the internet via a proxy.
Problem : Creative cloud goes through asking for corperate credentials which works fine. After signing in however Creative cloud spins with "loading Creative Cloud".
Analysis : Looking at the ACC.log and also wireshark I can see issues with DNS lookups which I fixed with a kludge. I have checked the certs and other KB things. One error I did see which confused me was Creative Cloud failing to get the proxy settings for IE in the ACC log.
Questions for the community: Has this sort of setup been done before? Before we started settting it up we did have meetings with Adobe and they agreed it was possible.