CORS Issue with better-auth in NestJS and Next Setup

Hey everyone,

I'm setting up authentication in my NestJS app using better-auth with a PostgreSQL database via Prisma. Everything seems to be correctly configured, but I'm running into a CORS issue when trying to sign up a user from my next front end.

Error Message

Access to XMLHttpRequest at 'http://localhost:3050/api/auth/sign-up/email' from origin 'http://localhost:3000' has been blocked by CORS policy: 

** My Setup**

 **NestJS Backend (`main.ts`)**

Access to XMLHttpRequest at 'http://localhost:3050/api/auth/sign-up/email' from origin 'http://localhost:3000' has been blocked by CORS policy: 

** My Setup**

 **NestJS Backend (`main.ts`)**

typescript
async function bootstrap() {
const app = await NestFactory.create(AppModule);

app.use('/api/auth', toNodeHandler(auth)); // Using better-auth middleware

app.use(json());

// Configure CORS middleware
app.use(
cors({
origin: 'http://localhost:3000',
methods: ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS'],
allowedHeaders: ['Content-Type', 'Authorization'],
credentials: true,
}),
);

// Global validation pipe
app.useGlobalPipes(new ValidationPipe());

await app.listen(process.env.PORT ?? 3050);
}
bootstrap();

Better-Auth Config (
/lib/auth.ts
/lib/auth.ts
)

const prisma = new PrismaClient();
export const auth = betterAuth({
database: prismaAdapter(prisma, {
provider: "postgresql",
}),
basePath: "/api/auth",
baseURL: "http://localhost:3050/api/auth",
emailAndPassword: {
enabled: true,
},
trustedOrigins: [
'http://localhost:3000',
],
advanced: {
defaultCookieAttributes: {
secure: true,

httpOnly: true,
sameSite: "none",
},
},
});

Next frontend auth config

import { createAuthClient } from "better-auth/react"

export const authClient = createAuthClient({
    baseURL: "http://localhost:3050",
    credentials: true,
})

import { createAuthClient } from "better-auth/react"

export const authClient = createAuthClient({
    baseURL: "http://localhost:3050",
    credentials: true,
})

Question
Is there anything I need to add to my better-auth configuration to properly handle CORS? Is there an additional middleware required in NestJS for better-auth to work with CORS?

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