when i invoke change email from my client 

` const UpdateEmail = await axios.post("/api/auth/change-email", {
        newEmail:values.email
      }, { withCredentials:true ,baseURL:process.env.NEXT_PUBLIC_SERVER_URL}); `
      
am always getting this response from the server

`2025-10-03T18:07:31.879Z ERROR [Better Auth]: Verification email isn't enabled.`

this is my auth betterauth config from my express server

`// utils/auth.ts
import { betterAuth } from "better-auth";
import { mongodbAdapter } from "better-auth/adapters/mongodb";
import { connectDB } from "./db";
import { createAuthMiddleware, openAPI,organization, username } from "better-auth/plugins";
import { sendEmail } from "./sendEmail";

let authSingleton: ReturnType<typeof betterAuth> | null = null;

export async function getAuth() {
  if (authSingleton) return authSingleton;

  const db = await connectDB();
  if (!db) throw new Error("Database not initialized");

  authSingleton = betterAuth({
  baseURL: process.env.NEXT_PUBLIC_URL,
  trustedOrigins: [
    'http://localhost:3000',
    'http://localhost:4000'
  ],
  database: mongodbAdapter(db),

  emailAndPassword: {
    enabled: true,
    requireEmailVerification: true,
    autoSignIn: false,
    sendResetPassword: async ({ user, url, token }, request) => {
      await sendEmail({
        to: user.email,
        subject: "Aqunest : Reset your password",
        text: `Click the link to reset your password: ${url}`,
        url,
        buttonText: `Reset Password`
      });
    }
  },

  // :key: must be globally enabled
  emailVerification: {
    enabled: true,
    sendVerificationEmail: async ({ user, url, token }, request) => {
      await sendEmail({
        to: user.email,
        subject: "Aqunest - Verify your email address",
        text: `Click the link to verify your email: ${url}`,
        url,
        buttonText: `Verify Email`
      });
    }
  },

  user: {
    changeEmail: {
      enabled: true,
      sendVerificationEmail: async ({ user, newEmail, url, token }, request) => {
        await sendEmail({
          to: newEmail, // :white_check_mark: always new email
          subject: "Aqunest - Verify your new email address",
          text: `Click the link to verify your new email: ${url}`,
          url,
          buttonText: `Verify Email`
        });
      }
    },
    additionalFields: {
      role: {
        type: "string",
        defaultValue: "user"
      },
      onboarding: {
        type: "string",
        defaultValue: "false"
      }
    }
  },

  plugins: [openAPI(), organization(), username()],
  advanced: {
    cookiePrefix: "Aqunest"
  }
});
console.log(
  "BetterAuth initialized. Email verification enabled:",
  authSingleton.options.emailVerification
);

  return authSingleton;
}`

i have tried everything nothing is working 
i have also tried to see if the email verification is enabled and it is true

`BetterAuth initialized. Email verification enabled: {
  enabled: true,
  sendVerificationEmail: [AsyncFunction: sendVerificationEmail]
}`

this is my express server.ts

`import express from "express"
import dotenv from 'dotenv'
import bodyParser from "body-parser";
import cookieParser from 'cookie-parser'
import MeteringRoutes from './routes/metering-route'
import RentalRoutes from './routes/Rental-route'
import cors from "cors"
import {getAuth} from "./utils/auth"
import { fromNodeHeaders, toNodeHandler } from "better-auth/node";
import { connectDB } from "./utils/db";

import "./logger/loggers" 
import winston from "winston";

dotenv.config();

const ExpressMainLogger = winston.loggers.get('ExpressMainLogger');


const app = express();


const allowedOrigins = [
  "http://localhost:3000",
  "https://your-frontend.com"
];

app.use(
  cors({
    origin: (origin, callback) => {
      if (!origin || allowedOrigins.includes(origin)) {
        callback(null, true);
      } else {
        callback(new Error("Not allowed by CORS"));
      }
    },
    credentials: true,
  })
);

// app.use(bodyParser.json())
// app.use(bodyParser.urlencoded())
// :white_check_mark: parses incoming JSON requests
app.use(express.json());

// (if you expect form submissions too)
app.use(express.urlencoded({ extended: true }));
app.use(cookieParser())//extract cookie from browser



const SERVER_PORT = process.env.SMART_METER_PORT

connectDB();

app.use("/api/auth", async (req, res, next) => {
    const auth = await getAuth();
    return toNodeHandler(auth)(req, res);
});

app.use("/api/metering/",MeteringRoutes);
app.use("/api/rental/",RentalRoutes);

app.get("/api/me", async (req, res) => {
    const auth = await getAuth();
    const session = await auth.api.getSession({
      headers: fromNodeHeaders(req.headers),
    });
  
    if (!session) return res.status(401).json({ message: "Not logged in" });
  
    res.json(session);
});
app.listen(SERVER_PORT,()=>{
    ExpressMainLogger.info(`server has started in port ${SERVER_PORT}`)
})`