WhatsApp error 3: API Method

Code 3 means the app or token making the request lacks the capability to call this particular method. It is a permissions problem expressed at the API-method level rather than the data level: the platform knows who you are, but the thing you are trying to do is not something your app has been enabled to do. On the Cloud API this typically surfaces when an app has not completed the WhatsApp product setup, has not been granted advanced access to a permission, or is trying to use a feature that requires a specific capability such as a business-management scope.

The HTTP status documented for it is 500, which is misleading; this is not a server fault and retrying will not change the outcome. Look at the code, not the status.

Your token can be perfectly valid and unexpired and still produce a code 3 if the permission set behind it does not include what the endpoint needs.

Document the exact permission set each service needs and generate tokens from a checklist rather than ad hoc. Keep one System User per environment with both WhatsApp scopes, and include a smoke test in deployment that calls one messaging endpoint and one management endpoint so missing scopes fail in CI instead of in production. Scope problems on a valid token can also surface as code 10 or 131005 depending on which layer refuses; the distinctions are mapped in the error-code guide.