Requesting for a list of post in graphQL gives error in Node js

Question

I'm watching a tutorial and coding exactly as the instructor. I get this error at a point in the lesson. I get this error in my browser : The below code is not mine, credits goes to maximilian schwarzmüller (Instructor).

Front End React function Responsible for loading posts :

loadPosts = direction => {
    if (direction) {
      this.setState({ postsLoading: true, posts: [] });
    }
    let page = this.state.postPage;
    if (direction === "next") {
      page++;
      this.setState({ postPage: page });
    }
    if (direction === "previous") {
      page--;
      this.setState({ postPage: page });
    }
    const graphqlQuery = {
      query: `
        {
          posts{
            posts{
              _id
              title
              content
              creator {
                name
              }
              createdAt
              }
            totalPosts
          }
        }
      `
    };
    fetch("http://localhost:8080/graphql", {
      method: "POST",
      headers: {
        Authorization: "Bearer " + this.props.token,
        "Content-Type": "application/json"
      },
      body: JSON.stringify(graphqlQuery)
    })
      .then(res => {
        return res.json();
      })
      .then(resData => {
        if (resData.errors) {
          throw new Error("Fetching Post Failed");
        }
        this.setState({
          posts: resData.data.posts.posts.map(post => {
            return {
              ...post,
              imagePath: post.imageUrl
            };
          }),
          totalPosts: resData.data.posts.totalPosts,
          postsLoading: false
        });
      })
      .catch(this.catchError);
  };

Server code attached : REMOVED

I'm attaching my whole code because I really don't know where the error is coming from. I basically replicated my instructor's code but it didn't work in mine like his did. The Udemy community was also unable to help.

EDIT : I found the problem, it was my mistake, I redirected with 401 in my token checking if block. I did exactly the opposite, I redirected if the user was authenticated.