# `400` - Missing client ID ## Description The `upvest-client-id` header is missing in the request. ## How to fix Provide `upvest-client-id` in the request header. ## Example ```http HTTP/1.1 400 Bad Request content-length: 176 content-type: application/problem+json date: Mon, 11 Oct 2021 10:42:01 GMT upvest-request-id: e7378103-7d45-4052-a049-7c9ac88d041c { "type": "https://docs.upvest.co/errors/missing_client_id", "status": 400, "title": "Missing client ID", "request_id": "e7378103-7d45-4052-a049-7c9ac88d041c" } ```