Hasura GraphQL POST request in JWT callback not working

[IsoPhoenix]

Hi! I'm new to next-auth and this community, so please bear with me/let me know if I'm breaking any rules.

I'm developing a next.js webapp that uses next-auth for authentication and is linked to a Postgres database through Hasura. I'm following this tutorial for the integration and trying to update the users table in my database via the JWT callback function. The full authentication process is still running and I can authenticate into my app, but it doesn't look the database is updating.

The actual graphql query works as intended when I prototype it in Hasura, so I don't think that's the source of the problem. Maybe something to do with how I'm writing the request (either in data-fetch.ts or data-fetch-methods.tsx)? I'm not really sure how to resolve this or how to debug this further, so I'd really appreciate any guidance you can provide!

I've attached the relevant code below:

// [...nextauth.js]
import { updateUser } from "../../../utils/data-fetch";

export default NextAuth({
  ....
  callbacks: {
    async jwt({ token, account }) {

      const userId = token.sub;
      const nickname = token.name;

      const test = await updateUser(userId, nickname, 0);
      console.log("Testoutput");
      console.log(test);
     // console logs undefined, which is unexpected

      // Role assignment
      const role = adminEmails.includes(token.email) ? "admin" : "user";
      token.role = role;
      return token;
    },
  ....
  }
})

// data-fetch.tsx
import { fetchGraphQLAdmin } from "./data-fetch-methods";

export async function updateUser(user_id, nickname, org_id) {
  const updateUserQuery = `mutation UpdateUser($userId: String!, $nickname: String, $orgId: Int) {
     insert_users(objects: [{
       id: $userId, name: $nickname, last_seen: "now()", organization_id: $orgId
     }], on_conflict: {constraint: users_pkey, update_columns: [last_seen, name]}
     ) {
       affected_rows
     }
   }`;

  const { errors, data } = await fetchGraphQLAdmin(
    updateUserQuery,
    "updateUserQuery",
    {
      userId: user_id,
      nickname: nickname,
      orgId: org_id,
    }
  );

  return data;
}

// data-fetch-methods.ts

export async function fetchGraphQLAdmin(queryString: string, name: string, variables: any) {
  const result = await fetch(
    "https://databaseurl.com",
    {
      method: "POST",
      body: JSON.stringify({
        query: queryString,
        operationName: name,
        variables: variables
      }),
      headers: {
        "X-Hasura-Admin-Secret": "admin-secret-here",
      }
    }
  );

  return await (result.json());
}

Thank you so much in advance!