Authentication in graphql

Question

I'm trying to add authentication in graphql, so only authenticated users can make a request to my server. But when I try to send the id in the Authorization header it doesn't send the information I want. It's a next project with ssr.

import { ApolloClient, InMemoryCache, createHttpLink } from '@apollo/client';
import { setContext } from '@apollo/client/link/context';
import { getAuth } from 'firebase/auth';
const httpLink = createHttpLink({
    uri: 'http://localhost:4000/graphql',
});

const authLink = setContext((_, { headers }) => {
    const user = getAuth().currentUser;
    return {
        headers: {
            ...headers,
            authorization: user?.uid ?? "null"
        }
    }
})
const client = new ApolloClient({
    link: authLink.concat(httpLink),
    cache: new InMemoryCache()
});


export default client;

I have the id of the user in a redux context, so I tried to use store.getState(), but it didn't work. Also I've tried with firebase getAuth, so I send the uid.