The URL is NOT blocked by our firewall. I administer the firewall, so that was easy to check. We don't use proxies and blockers and security software have been pushed aside or disabled. I even tried this on a bare machine.
As far as the provisioning tool, I haven't used it. However, I did use this serial number on an installation and it validated perfectly fine, with the security software turned on. That's how we discovered Adobe's obstructive, useless "constant sign-in required" which would not be a proper set-up for that multi-user workstation. (PLEASE DO NOT try to argue why or why not this would not function for that workstation. That is not the topic here. The topic is getting the customization wizard to function properly.) I did not sign in. After researching how to disable this idiocy, I stayed on-line and did a proper removal, allowing the Adobe un-installer to do the work. Ultimately, the key code has already been demonstrated to be valid and is not in use.
Let's remember that Adobe regularly publishes broken software with lame, hard-coded requirements. For example, many Adobe installers require that one be logged in as the local machine administrator, not just a user with local admin privileges. Also, the local admin CANNOT be renamed, which is a step many shops take for security reasons, but Adobe can't figure out how to require only admin priv's, rather than hard coding a specific username. In the previous iteration of the Customization Wizard, version 11, there was a hard-coded leftover from version 10 where an executable would get called from the version 10 folder, which does not exist on a version 11 installation of the customization wizard. The workaround was to manually create the version 10 folders and copy the v11 executable in question into the folder, but run the main program from the proper version 11 folder. All that to point out that Adobe regularly publishes broken software.
Now, what mysterious little ticks are broken in the DC version of CW & how do I work around them?