### Bad request example: POST /sms with invalid sender ID

Source: https://vertexsms.com/docs

Shows a POST request to the VertexSMS API with an invalid sender ID, resulting in a 400 Bad Request. The request includes required headers: Content-Type, Accept, and X-VertexSMS-Token. The response contains a JSON error message explaining the invalid 'from' field.

```http
POST /sms HTTP/1.1
Host: api.vertexsms.com
Content-Type: application/json
Accept: application/json
X-VertexSMS-Token: eB52vNTPL9fO3rDrx8pYmVnj6nqceHNhnqceHNh
{
  "to": "37069912345",
  "from": "invalid sender ID",
  "message": "Test SMS 001"
}
```

```http
HTTP/1.1 400 Bad Request
Content-Type: application/json
{
  "message": "Invalid value for field 'from'. Sender ID must either be a valid MSISDN or an alpha-numeric string (max. length: 11 characters), which may consist only of upper+lower-case latin letters, digits, spaces and dots."
}
```

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