SMTP

Giả lập phản hồi 252 Cannot Verify User

The server cannot verify the user but will accept the message and attempt delivery. This is often returned in response to VRFY when the server intentionally hides user information.

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1 Phản hồi HTTP

Phản hồi HTTP
HTTP/1.1 252 Cannot Verify User
Content-Type: application/json
Date: Tue, 25 Feb 2026 12:00:00 GMT
Content-Length: 21

{
  "status": "success"
}

2 Kiểm tra với curl

terminal
curl -i https://httpbin.org/status/252

3 Trả về 252 Cannot Verify User trong Framework của bạn

django
from django.http import JsonResponse


def my_view(request):
    return JsonResponse(
        {"status": "success"},
        status=252,
    )
flask
from flask import Flask, jsonify

app = Flask(__name__)


@app.route("/endpoint")
def my_endpoint():
    return jsonify({"status": "success"}), 252
fastapi
from fastapi import FastAPI
from fastapi.responses import JSONResponse

app = FastAPI()


@app.get("/endpoint")
def my_endpoint():
    return JSONResponse(
        content={"status": "success"},
        status_code=252,
    )
express.js
// Express.js
app.get('/endpoint', (req, res) => {
  res.status(252).json({"status": "success"});
});
spring boot
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import java.util.Map;

@RestController
public class MyController {

    @GetMapping("/endpoint")
    public ResponseEntity<Map<String, Object>> myEndpoint() {
        return ResponseEntity
            .status(252)
            .body(Map.of("error", "cannot_verify_user",
                         "message", "Cannot Verify User"));
    }
}
go net/http
package main

import (
    "encoding/json"
    "net/http"
)

func myHandler(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("Content-Type", "application/json")
    w.WriteHeader(252)
    json.NewEncoder(w).Encode(map[string]string{
        "error":   "cannot_verify_user",
        "message": "Cannot Verify User",
    })
}
ruby on rails
class MyController < ApplicationController
  def my_action
    render json: {"status": "success"},
           status: :cannot_verify_user
  end
end
asp.net core
// ASP.NET Core Minimal API
app.MapGet("/endpoint", () =>
    Results.Json(
        new { error = "cannot_verify_user", message = "Cannot Verify User" },
        statusCode: 252
    )
);

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