Hi everybody! When trying to link a Facebook account to a pre-existing Google account, we occasionally run into this error:

The browser does not contain the necessary cookie to resume the session. This is a security violation and was blocked. Please clear your browser's cookies and cache and try again!

However when I restart the flow, this does not happen again. Can somebody shed a light on what the problem might be and how to tackle it?

Hello @ambitious-gigabyte-21534 This error might be related to the way Ory handles cookies and CSRF (Cross-Site Request Forgery) mechanisms. Ory uses HTTP cookies to store sessions when accessed via a browser. If the necessary cookies are not present or are not correctly set, it might trigger Ory's anti-CSRF mechanisms and cause the error you're seeing. Here are a few things you could check: 1. Browser Settings: Make sure the browser is not discarding cookies. For instance, if you're running the OAuth2 flow in separate browsers, or in a browser with incognito mode, or in a browser like Brave in "No-Tracking" mode, it might discard cookies. 2. Running Multiple OAuth2 Flows: If you're trying to do two OAuth2 flows at the same time in the same browser, it might cause issues. 3. Cookie Same-Site Mode: Check if you have changed the Cookie SameSite behavior. If this is the default value (you didn't change it), this shouldn't be an issue. 4. AJAX Requests: If you're using AJAX to call

/oauth2/auth

, note that it isn't allowed and not possible with OAuth2. This endpoint can only be accessed using a normal browser request by clicking a link or redirecting the end-user's browser to that endpoint. 5. Reverse Proxy or Load Balancers: If you're running Ory Hydra behind a reverse proxy that strips the Cookie header, it might cause issues. To debug these issues, you can use tools like the Chrome DevTools. In Chrome DevTools, go to the Application tab and open the Cookies section. Look for

Cookie

and

Set-Cookie

HTTP headers. Inspecting the Network tab and looking for the same headers can also help you find the root cause of your problems.