Using avatar SDK 3.9 or higher, the build & publish button does not work for any avatar attempting to be uploaded. It just greys out the SDK and there are no errors logged in Unity.

I've attempted to solve this through a clean reinstall of VCC and Unity, I've tried a VPN, creating a new project, reloading the SDK, etc etc, all to no avail.

The last version that worked consistently for me was 3.7.6. Since that version is deprecated, I have been unable to upload any avatars, including the basic robot one included in the SDK.