There could be several reasons why you're getting a 502 error from your Ory Tunnel when accessing the registration flow. Based on the knowledge sources, here are the most common issues and solutions: ## Common Causes for Tunnel Issues ### 1. CORS and Cookie Issues Ory uses HTTP cookies for session management and CSRF protection. When developing locally, cookies must be properly set on the same domain: - Make sure you're consistently using either

localhost

or

127.0.0.1

, but not both interchangeably, as they're treated as different domains by browsers [Ory Security Model](https://www.ory.sh/docs/security-model). - Cookies set on

localhost

won't be sent in requests to

127.0.0.1

and vice versa [Local Development](https://www.ory.sh/docs/getting-started/local-development#local-development). ### 2. Tunnel Configuration Check if your tunnel is properly configured: - Ensure you're using the

--dev

flag when running the tunnel for local development:

ory tunnel --dev <http://localhost:3000>

- The

--dev

flag disables security checks that might cause issues during local development [Integrate authentication into Vue.js + API](https://www.ory.sh/docs/getting-started/integrate-auth/vue). ### 3. SDK Configuration If you're using the Ory SDK, make sure it's properly configured: - Set

withCredentials: true

in your SDK configuration to ensure cookies are sent with cross-origin requests [Integrate authentication into React](https://www.ory.sh/docs/getting-started/integrate-auth/react#run-ory-apis-on-localhost). - Use the correct SDK version. There have been issues with older SDK versions like

@ory/kratos-client

- consider using

@ory/client

instead [Github Issue #53](https://github.com/ory/network/issues/53). ### 4. CSRF Protection Ory implements CSRF protection for all flows: - When submitting forms, ensure you're including the CSRF token from the hidden input field named

csrf_token

[Integration basics](https://www.ory.sh/docs/kratos/bring-your-own-ui/custom-ui-basic-integration#debug). - The browser should automatically send the CSRF cookie, but you must manually add the CSRF token to the request body. ## Troubleshooting Steps 1. Check if your application and Ory Tunnel are running on the same top-level domain. 2. Verify that you're using the correct URL format when accessing the registration flow. 3. Ensure your SDK is properly configured with

withCredentials: true

. 4. Check browser console for any CORS or cookie-related errors. 5. Try restarting the Ory Tunnel with the

--dev

flag. If you continue experiencing issues, you might want to check the Ory Tunnel logs for more specific error messages that could help identify the root cause. I hope this helps you resolve the 502 error. Let me know if you need more specific guidance!