That “error – user not joined” usually means the web call session is being created, but the client never actually connects to the call (browser blocks mic, session token not attaching, or the join event isn’t firing). When that happens, Retell ends it immediately at 0:00, regardless of the prompt. I’ve seen this exact behavior before especially with web calls freezing on test call. If you want, DM me the setup details (web call config + how you’re initializing the session) and I can point out where it’s breaking. It’s usually a small but non-obvious fix.