There could be several reasons why Ory's self-service is not returning a code in an API code flow. Here are a few possibilities based on the provided knowledge sources: 1. Misconfiguration: As mentioned in the [Hydra documentation](https://www.ory.sh/docs/hydra/debug#oauth-20-authorize-code-flow-fails), the most likely cause for OAuth 2.0 authorize code flow failures is misconfiguration. 2. Missing ID Token: In the [Ory Kratos User Registration](https://www.ory.sh/docs/kratos/self-service/flows/user-registration#registration-with-google-facebook-github--openid-connect--oauth-20-1) and [User Login](https://www.ory.sh/docs/kratos/self-service/flows/user-login#login-with-google-facebook-github--openid-connect--oauth-20-1) documentation, it's mentioned that a possible validation error is a missing ID Token. If the ID Token is missing, the authentication fails and no code is returned. 3. CSRF Violation: According to the [Ory API Reference](https://www.ory.sh/docs/reference/api), if a CSRF violation occurs, the flow cannot be fetched. 4. Session Inactive: If no Ory Session is found, the flow cannot proceed. 5. Identity Mismatch: If the flow was interrupted with

session_refresh_required

but some other identity logged in instead, the flow cannot proceed. 6. Invalid Return Address: If the requested

?return_to

address is not allowed to be used, the flow cannot proceed. Please check your configuration and the error messages returned by the API to identify the exact cause of the issue.