# MRPC_VALIDATION

> Terminal route error (`/{mt4|mt5}/{id}/…`): a parameter is missing or invalid.

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

HTTP 400. Nothing reached the broker.

**Likely causes:**

- A required query or body field is missing.
- A value has the wrong type or range.

**What to do:** Fix the request; the message names the parameter.

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

Listed under [Compatibility error names](https://tickwire.io/docs/errors/#compatibility-error-names) in [Errors](https://tickwire.io/docs/errors/). Send the error's `requestId` to support and we can find the request.