A 403 Forbidden error for an OIDC client in Ory Kratos typically indicates that the request is not authorized to access the resource. Based on the knowledge sources, here are some common causes and troubleshooting steps: 1. CSRF Protection: If you are accessing Ory Identities APIs and encounter a 403 error, it may be due to Ory's anti-CSRF mechanisms. This can happen if cookies are not set correctly, or if you are using a domain on the public suffix list (PSL), which prevents cookies from being set. Make sure you are using a subdomain that is not on the PSL and that your application's cookie settings are correct. For SPAs, ensure that AJAX requests include credentials (e.g.,

credentials: 'include'

in fetch). For server-side apps, forward the

Cookie

header when fetching flows. A specific error you might see is

security_csrf_violation

if the domain is misconfigured [CSRF troubleshooting](https://www.ory.sh/docs/troubleshooting/csrf/). 2. Insufficient Access Credentials: If the client credentials (such as client ID and secret) are missing, incorrect, or not authorized for the requested resource, a 403 error can occur. This can also happen if the OAuth2 client is misconfigured or if the request is missing required headers (such as the Authorization header for bearer tokens) [Missing or incomplete basic auth header in token request](https://github.com/ory/network/issues/332). 3. API Error Response: The Ory APIs, including Kratos, return a standard JSON error format for 403 errors. The error object may include an

id

field with values like

feature_not_available

or

quota_exceeded

, or a message indicating insufficient permissions or a forbidden action [Ory API Reference](https://www.ory.sh/docs/reference/api). 4. WebSocket and Oathkeeper Integration: If you are using Oathkeeper with bearer tokens and encounter 403 errors on WebSocket connections, it may be due to access credentials not being sufficient or the session check failing. Review your Oathkeeper rules and ensure the

check_session_url

and token handling are correct [Problem with websocket requests access check via oathkeeper](https://github.com/ory/network/issues/76). If you need more specific guidance, please provide the exact error message or context in which the 403 error occurs. The knowledge sources do not provide a single root cause, but the above are the most common scenarios for 403 errors in Ory Kratos and OIDC client integrations.

When integrating an external OIDC provider into Ory Kratos and encountering a 403 Forbidden error, the most common causes—according to the knowledge sources—are related to CSRF protection, cookie handling, and domain configuration. Key troubleshooting steps: 1. Check CSRF Protection and Cookies Ory Kratos enforces CSRF protection for all flows. If your domain is on the public suffix list (PSL), cookies required for CSRF protection cannot be set, resulting in 403 errors. Make sure you are using a subdomain that is not on the PSL. For SPAs, ensure AJAX requests include credentials (e.g.,

credentials: 'include'

in fetch). For server-side apps, forward the

Cookie

header when fetching flows. If you see an error like

security_csrf_violation

, this is a strong indicator of a CSRF or cookie issue. [CSRF troubleshooting](https://www.ory.sh/docs/troubleshooting/csrf/) 2. Review OIDC Client Configuration Double-check that your OIDC client credentials (client ID, secret, redirect URIs) are correct and match what is configured in both Kratos and the external provider. A mismatch or missing configuration can result in forbidden errors, though the knowledge sources do not provide a specific example for this. 3. Check for Insufficient Permissions If the OIDC client is not authorized to access the requested resource, or if required scopes are missing, a 403 can occur. Ensure the client has the necessary permissions and scopes configured on the external provider. 4. Inspect Error Messages Ory APIs return a standard JSON error format for 403 errors, which may include a message or reason field. Review the error response for clues about the root cause. If you have already checked these areas and are still encountering issues, the knowledge sources do not provide further specific debugging steps for this scenario. For more advanced troubleshooting, you may need to consult Ory's community forums or open a discussion with detailed logs and configuration snippets. > The knowledge sources do not contain more detailed, step-by-step debugging instructions for this specific 403 error when integrating an external OIDC provider into Kratos. If you need more targeted help, please provide the exact error message or logs you are seeing. [CSRF troubleshooting](https://www.ory.sh/docs/troubleshooting/csrf/)