Next-Auth callback error POST http://localhost:3000/api/auth/callback/credentials/ 401 (Unauthorized)

I am new in the next js. I tried to use next-auth for authentication but I got the below error. Does anyone help me?

import NextAuth from 'next-auth';
import CredentialsProvider from 'next-auth/providers/credentials';
export default NextAuth({
    providers: [
        CredentialsProvider({
            name: 'credentials',
            credentials: {},
            async authorize(credentials, req) {
                const payload = {
                    username: credentials.username,
                    password: credentials.password
                };

                const res = await fetch(credentials.signInUrl, {
                    method: 'POST',
                    body: JSON.stringify(payload),
                    headers: {
                        'Content-Type': 'application/json',
                    }
                });
                const user = await res.json();
                if (!res.ok) {
                    throw new Error(user.message);
                }
                // If no error and we have user data, return it
                if (res.ok && user) {
                    console.log('Next-Auth user ', user);
                    return user;
                }

                // Return null if user data could not be retrieved
                return null;
            }
        })
        // ...add more providers here
    ],
    // secret: process.env.JWT_SECRET,
    pages: {
        signIn: '/auth/login',
    },
    callbacks: {
        async jwt({ token, user, account }) {
            if (account && user) {
                return {
                    ...token,
                    username: user.username,
                    idToken: user.idToken,
                    refreshToken: user.refreshToken,
                    roles: user.roles
                };
            }

            return token;
        },

        async session({ session, token }) {
            session.user.accessToken = token.accessToken,
            session.user.refreshToken = token.refreshToken,
            return Promise.resolve(session);
        }
    },
    // Enable debug messages in the console if you are having problems
    debug: process.env.NODE_ENV === 'development'
});

and the signin page /auth/signin

const handleLoginSubmit = async (e) => {
        e.preventDefault();
        const signInUrl = `${process.env.NEXT_PUBLIC_API_SERVICE_BASE_URL}/api/v1/User/Login`;
        const res = await signIn('credentials', {
            username: loginInput.username,
            password: loginInput.password,
            signInUrl,
            redirect: false,
        });
}

But I got the error POST http://localhost:3000/api/auth/callback/credentials/ 401 (Unauthorized)

No authorization applied in _app.js

export default function MyApp({ Component, pageProps }) {
    if (Component.getLayout) {
        return <LayoutProvider>{Component.getLayout(<Component {...pageProps} />)}</LayoutProvider>;
    } else {
        return (
            <LayoutProvider>
                <Layout>
                    <Component {...pageProps} />
                </Layout>
            </LayoutProvider>
        );
   }
}

Please any one expert help me.