An enterprise utilizes the source code of a network software product licensed under the AGPL v3. It modifies the source code but does not share the changes with the original developer and copyright holder, and keeps the changes private. It then hosts the modified version within its servers, but does not distribute the source code as a bundle to any third parties. It allows a closed group of its authenticated customers (not the general public) to interact with this modified product - via web services - fronted through a web portal of the enterprise.
Is the enterprise violating any of the terms of the AGPL v3? If so, which exactly?