# unsupported_response_type

> OAuth (Sign in with Tickwire): only response_type=code is supported (shown on the sign-in error page).

Source: https://tickwire.io/docs/errors/unsupported_response_type/

HTTP 400.

**Likely cause:** The app used the implicit flow or another response type.

**What to do:** Use response_type=code with PKCE (S256).

**Retry:** No. The same request gets the same answer; change something first.

Listed under [Sign in with Tickwire (OAuth)](https://tickwire.io/docs/errors/#sign-in-with-tickwire-oauth) in [Errors](https://tickwire.io/docs/errors/). Send the error's `requestId` to support and we can find the request.