---
title: Troubleshooting Google OAuth authentication
slug: how-tos/_RG--tr
createdAt: 2025-10-21T11:46:33.000Z
---

## No reply address provided

Either the redirect URI is incorrect, the BaseURL is misconfigured, or Factry Historian was not restarted after the BaseURL was changed.

## Error: redirect\_URI\_mismatch

The redirect URI configured in Google Cloud does not match the one registered in Factry Historian.
Verify:

- In **Google Cloud Console → APIs & Services → Credentials → OAuth Client ID → Authorized redirect URIs**, confirm the value matches exactly the Historian BaseURL + `/api/auth/<providername>/callback`.
- In **Factry Historian → Configuration → Server Settings → General → BaseURL**, confirm it matches your public HTTPS URL.
- Restart Factry Historian if you changed the BaseURL.

## Error: invalid\_client / invalid\_client\_secret

The Client ID or Secret copied into Historian do not match those in Google Cloud.

- Re-copy both values from Google Cloud and update them in **Historian → Authentication Providers**.

## Error: invalid\_request

The OAuth consent screen was not completed or not published.
In **Google Cloud Console → OAuth consent screen**, verify that:

- The app is published.
- The User Type (**Internal** / **External**) matches your organization’s needs.

## Blank page after Google login

The Historian web UI fails to receive the callback.
Possible causes:

- HTTPS not correctly configured.
- Proxy not forwarding headers (`X-Forwarded-Proto`).
- BaseURL mismatch.
  → Confirm Historian is reachable over valid HTTPS and the BaseURL is identical to the external URL.

## User logs in but sees “Access Denied”

Historian found the user but no permissions were granted.

- Ensure the user exists in Historian with a username exactly equal to the Google login (usually the email address).
- Add the user to the appropriate groups in Historian.

## Error: 400 invalid\_request or unauthorized\_client

The consent screen or credentials are incomplete.

- Confirm the app in Google Cloud has a published OAuth consent screen and a valid Client ID/Secret.
- Delete and recreate the OAuth Client ID if the configuration seems corrupted.

## Browser shows certificate warning or mixed-content error

Historian must be served over HTTPS for Google OAuth to work.

- Install a valid TLS certificate for your Historian domain.
- Avoid using IP addresses or localhost URLs in redirect URIs.

## User not found in Historian

Historian does not auto-create users.

- Add the user manually in **Historian → Users → Create User**, with a username equal to their Google email address.

:::hint{type="info"}
Don't spot your error? Contact Factry support.
:::