Hi @active_Wave6c71,
Thanks for the thorough follow-up, and for running the guest sign-in test. That detail (guest works, Enterprise ID sign-in gets blocked) is genuinely useful for narrowing this down.
Since you're on Enterprise ID rather than Federated ID through Google, this isn't the under-18 Google Admin Console approval path, so you can set that aside. A staff/educator account set to 18+ wouldn't hit that particular gate. The error you're seeing is coming from an app-authorization policy on your Adobe org, which is separate from anything you'd configure on the Google side.
One thing worth checking in the Adobe Admin Console first: under Products > App Integrations, there's an authorization policy that controls whether users can grant third-party apps access to your organization's content. Even with app integrations broadly allowed, a connector can still be blocked at authentication if the policy is set to block access, or if the specific app hasn't been permitted. It's worth confirming how that policy is configured for your org. Reference: https://adobe.ly/3UijQeE
If the policy is already set to allow access and the Enterprise ID sign-in is still blocked, that points to a restriction on your organization's account that we'll want to look at directly. In that case, please open a case from the Admin Console > Support tab, and include the exact error, the guest-vs-Enterprise ID test result you shared here, and that you're authenticating with the ChatGPT Adobe connector. That'll let the team check the specific policies applied to your org.
To answer your direct question: no, this isn't a limitation of the K-12 license itself. The block is about how third-party app authorization is configured for your org, not the plan type.
Please let us know what you find, we're happy to keep helping.
Thanks,
^AV