How can I call the signIn function in SSR?

[seungkum]

I am trying to implement next-auth using Next.js 14. The method I want to achieve is:

When I call localhost:3000/api/login, I want to see console.log("start authorize !!!!") in the console.

However, while it works correctly when implemented in CSR, it doesn't work when I try to implement it in SSR. Is there something I'm doing wrong?

[app/api/login/route.ts]

`import { NextResponse } from "next/server";

export async function GET() {
  const csrfToken = await fetch("http://localhost:3000/api/auth/csrf", {
    method: "GET",
    headers: {
      "Content-Type": "application/json",
    },
  })
    .then((res) => res.json())
    .then((data) => data.csrfToken);

  const response = await fetch(
    "http://localhost:3000/api/auth/callback/credentials",
    {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        code: "200",
        csrfToken,
      }),
    },
  );

  if (!response.ok) {
    return NextResponse.json({ error: "Login failed" }, { status: 401 });
  }

  return NextResponse.json({ success: "Login success" }, { status: 200 });
}

[app/api/auth/[...nextauth]/route.ts]

`import NextAuth, { NextAuthOptions } from "next-auth";
import CredentialsProvider from "next-auth/providers/credentials";

const authOptions: NextAuthOptions = {
  providers: [
    CredentialsProvider({
      id: "credentials",
      credentials: {
        code: { label: "Code", type: "text" },
      },
      async authorize(credentials): Promise<any> {
        console.log("start authorize !!!!!! ");
        return null;
      },
    }),
  ],
};

const handler = NextAuth(authOptions);

export { handler as GET, handler as POST, authOptions };

Does anyone know why this behavior is different between SSR and CSR? Any guidance would be appreciated.