The devs pushed a backend update today November 24th that should have resolved the activation and model download issues being seen in version 2.6.4 of Video Enhance AI. This is not an update to that version of the app, but just an update with the server side that it is connecting to.
If this works for users, please confirm here and if you are still seeing issues, please message the support team directly at help@topazlabs.com
