Authentication failure blocking Enterprise Workspace accounts

### What happened?

I was signed in with my Google Workspace account and a Google Cloud Project ID configured as described in the [authentication documentation](https://geminicli.com/docs/get-started/authentication/#set-your-google-cloud-project). This setup had been working without (auth) issues.

Last week, when opening a new session, I suddenly get this error:

> Failed to sign in. Message: You do not have a valid license of this product. Please contact your administrator to request a license. If you are not an enterprise user and believe you are receiving this message as an error, please try using the latest version and logging in again. (#3501)

This occurred without any changes to the account, license, cloud project, project configuration, or Gemini CLI installation. The account holds a valid license that should still be supported by Gemini CLI.

After encountering the error, I attempted to:
- update to the latest stable, preview, and nightly releases
- install previous versions to rule out a regression
- log out, clear all local authentication data, and log back in

None of these resolved the issue.

### The issue persists across **all** of the latest versions:

- [v0.55.1](https://github.com/google-gemini/gemini-cli/releases/tag/v0.55.1)
- [v0.56.0](https://github.com/google-gemini/gemini-cli/releases/tag/v0.56.0)
- [v0.57.0](https://github.com/google-gemini/gemini-cli/releases/tag/v0.57.0) **[Latest]**
- [v0.58.0-preview.0](https://github.com/google-gemini/gemini-cli/releases/tag/v0.58.0-preview.0) **[Latest preview]**
- [v0.59.0-nightly.20260826.g64b5b79a6](https://github.com/google-gemini/gemini-cli/releases/tag/v0.59.0-nightly.20260826.g64b5b79a6) **[Latest nightly]**

### What did you expect to happen?

I expected to be able to use Gemini CLI, as this setup had been working previously.

### Client information

Client Information

```console
> /about
| CLI Version 0.57.0
| Git Commit 6b0ae9a6c
| Model Auto
| Sandbox no sandbox
| OS darwin
| Tier Gemini Code Assist
```

### Login information

**Auth method**: OAuth / Google Workspace account
with a Google Cloud Project ID configured _(as described in the [authentication documentation](https://geminicli.com/docs/get-started/authentication/#set-your-google-cloud-project))_.

**Tier**: `Gemini Code Assist`

### Anything else we need to know?

Additional information

@gemini-cli Do **NOT** label this issue as `status/possible-duplicate` of #28912. The reasons are outlined below.

# Why this is not a duplicate

While this issue describes the same authentication failure, the original issue #28912 has been "stuck" for over 7 days with no response. The bot requested additional information, which was subsequently provided by the original author and at least 7 other affected users, yet the bot never re-evaluated, re-classified, or removed its `status/need-information` label. Tagging the bot produced no response either. There is currently **no** working path forward on #28912, and opening this issue is necessary to escalate visibility.

## What's wrong with the current triage of #28912

Issue #28912 was created 7 days ago.

The triage bot initially added the following labels:
- `area/enterprise`
- `kind/bug`
- `priority/p2`
- `status/bot-triaged`
- `status/need-information`

A day later the bot removed the label `area/enterprise` and added label `area/agent`.

The bot's response read:
> This issue reports a login failure due to licensing errors. Please provide your CLI version and verify if the issue persists in the latest release.

Several of these labels and the bot's interpretation are incorrect:

- **`area/enterprise` (removed)**: This issue occurs specifically with Enterprise Google Workspace Accounts. Removing the `area/enterprise` label was wrong, this is an enterprise issue. (Swapping it for `area/agent` does not capture the scope.)

- **`priority/p2`**: The issue entirely prevents specific Enterprise users from using Gemini CLI. By the priority definitions of this repository, `priority/p2` is _"Important but can be addressed in a future release."_ An auth-blocking bug affecting paying enterprise customers for over a week should at minimum be `priority/p1` _"Important and should be addressed in the near term."_.

- **`status/need-information`**: The bot asked for the CLI version. That information, and substantially more, has been provided by the original author as well as several other affected users over the past 7 days. The bot has failed to re-evaluate, re-classify, or remove the `status/need-information` label, and has not responded in any way since its initial message.

## Mischaracterization/misinterpretation of the issue

The bot described this as a "login failure due to licensing errors." This framing is misleading. The affected users have valid licenses and tiers that Gemini CLI should support. The error message displayed mentions licensing, but by every available indication the licenses themselves are valid and correctly provisioned. The root cause is unknown. The licensing error is a symptom, not the cause. Framing this as a licensing error risks sending it down the wrong investigation path.

Start with the authentication documentation and reproduce the failure using the reported Google Workspace account and Google Cloud Project ID. Compare the behavior across the listed CLI versions and inspect the /about output; done means a valid Enterprise Workspace account can authenticate without the licensing error.

Written by the indexing model from the issue text.