Error Response
| Status Code | Code | Message |
|---|---|---|
| 400 | invalid_request | Invalid email template |
| 400 | invalid_request | Invalid OTP |
| 400 | invalid_request | Invalid request |
| 401 | unauthorized | Unauthorized |
| 402 | error_insufficient_credit | Error insufficient credit |
| 402 | error_expired_credit | Error expired credit |
| 500 | Internal_server_error | Internal sever error |