(This is a bug report which I prevoiusly posted in S3 bugs by mistake. Since posting this I've also tried relocating ProTools to the desktop and disabling my firewalls based on comments in other forums, to no effect)
64-bit Windows 7 Ultimate, Intel core i7-6700K CPU 4.00 GHz, 16 GB RAM, running ProTools 12.5.2
In collaboration tools, both the "invite another user" and "artist chat" buttons create a blank popup window that never populates (waited up to 20 minutes). No error message. I can close the window and carry on editing. None of the buttons in the track collaboration function appear to do anything at all, whether in the universal settings or the mixing and mastering window. They do not react when selected, whether before or after editing, except for the universal auto buttons, which light up when selected but don't appear to do anything else. Also, no associated error messages.
In my project, the collaboration tool show that I have uploaded material to the cloud. Checking my account online confirms this. I've created a profile to join the artist community, and I've optimized my PC as per the instructions. I've rebooted the whole system several times, deleted the project and started over several times, and tried to access collaboration tools from the drop down menu as an alternative.